Albert Little, a former Protestant who is now Catholic, wrote a brief piece in which he warns people (tongue firmly in cheek) how to avoid falling for Catholicism as he did. I find myself in the opposite boat--a former Catholic who is now Protestant. So what is written below is written in the same tone as Little's piece: a friendly anti-apologetic, in my response to him. I hope it will be received in the same winking tone that it is written, while also pointing out some true points of consideration. I personally do not know him, but perusing his site he seems like a witty and fun guy. (It might help to read the original link above to get the tone I'm going for.)
So, if you are a Protestant and want to know what it takes to become Catholic, let me help you with the following eight steps:
1) Read Scott Hahn (but don't think about it too much)
When I first converted to Protestantism, my grandfather (also my godfather, and we have a great deal of mutual spiritual respect) gave me Hahn's famous book, Rome Sweet Home. In it, Scott and Kimberly share their story of how they (as Presbyterian seminary students) ended up as Catholics. Like all conversion stories, it has some universal elements that will appeal to all of us, and it is a sincere story which clearly excites the Hahns and therefore is fun to read.
However...if you want to convert to Catholicism, be careful that you don't read too closely into Hahn's book. You might find him making bold statements which are easily disprovable from Scripture, such as saying that Paul never taught justification by faith in Scripture--and conveniently ignoring things like Galatians 2:16 and literally dozens of others.
If you step back out of Hahn's excitement and read it again, the story might take on a slightly different slant: that of a zealous Bible student who (as many do during seminary) questions everything that they are taught by their authority figure. But rather than just debate or research, Hahn spends five years attending Mass every day, prays the Rosary an hour every day, and buys a priest's library and spends seven hours per day reading it. His marriage nearly crumbles in the process, with his wife feeling betrayed, lonely, and even suicidal. She eventually converts after five years, but you are left wondering whether she is trying to save her marriage or has had an actual doctrinal shift in her mind. Regardless, neither her conversion nor Scott's comes across as a logical, reasoned, Scriptural conclusion--but rather as an emotional change. (Which does not, by the way, mean it isn't real: it just means it isn't as convincing if you have doubts of Catholicism.)
So the Hahns' story does have a lot to commend it to the questioning Protestant, but just be careful that you don't read it too closely--if so, you will find yourself saying, "Really? Is THIS the best Catholic apologetic book?" So just skim it, please...don't read too deeply.
2) Read Church history (but not all that far back)
My aunt converted from Baptist to Catholicism, and for her one of the major attractions was how old Catholicism is, going "all the way back to Peter." Similarly, Little found that reading about the Reformation, that Luther and the Reformers were not as heroic as he had in mind.
There is no doubt that MANY churches today, particularly of the Baptist/evangelical variety, exist in a virtual historical vacuum. They neither know nor care about the past, and as such as doomed to repeat past heresies and mistakes. In this regard, Catholicism seems like a stable tower in a storm, which has stood for thousands of years and whose doctrine is stable.
So studying Church history can absolutely help you become Catholic.
BUT...stop at about the 11th century. Don't go back further. The Catholic's history of the medieval period and forward is pretty well documented and has a lot to attract people to it, for sure. But when you go back earlier in your studies, you might accidentally discover that the ancient churches--those from the 1st, 2nd, 3rd, and early 4th centuries--really don't resemble modern Catholicism at all. Indeed, it may appear that the 4th-10th centuries saw a radical shift in church politics, structure, and doctrine, and from this "proto-Catholic" church came what we call Orthodoxy and Catholicism. But your journey to Rome may falter once you realize that this "early" Catholic church was as far removed from the time of the apostles as we today are removed from the landing at Plymouth Rock.
(Oh, and definitely DO NOT attempt to trace the line of Popes back to Peter and verify it with non-Catholic sources.)
3) Read the Early Church Fathers (but read them as though they were written yesterday and use modern Catholic theological terms)
Another great source of influence in your journey to Catholicism can be the early church authors, the people who write just after the apostolic authors of the New Testament. They were the students of the apostles and therefore can help us understand their mindsets.
Now if you are going to study the Early Church Fathers to help you get to Roman Catholicism, you need to do two things. First, you need to give them more weight than the Bible. If the Biblical apostle says something that an early church father contradicts, then you should assume that the church father is telling us what the apostle really meant, and the apostle just worded it improperly. Assume that since they were the apostles' students, their writings must be absolutely 100% in alignment with what their teachers taught and wrote as well. (Ignore what we saw with Scott Hahn, where sometimes a student DOESN'T follow exactly the theology of his teacher. Assume that for the early church fathers, that didn't happen.)
Second--and this is critical!--you must NOT read it in context. Read the terms as they are understood today. If you read the term "bishop" assume it means someone in an administrative office who has several priesthoods under him. Definitely do NOT study the time, and learn that the term 'bishop' is a common term in Roman communities meaning the financial leader of any club, and therefore is identical with the Jewish "presbyter"--in other words, the bishop in this case would be the pastor of the local church, not a regional head of religion.
It is VERY important for your road to Catholicism that you do not let the Scriptures or the Early Church Fathers get too "Jewish" on you. That makes the faith Near Eastern, rather than Western. That tends to make what they say and do seem very different from the medieval Western Christianity of Rome. Far safer is if you divorce yourself of the Anglican and Protestant ideas of NT Wright and Scot McKnight, which are so insistent that we read these Jewish authors in a Jewish way.
4) Start hanging out with Catholics.
(Out of character) Okay, I can't really lampoon this part of Little's article, because I think you SHOULD hang out with great Catholics--regardless of whether you are Catholic or Protestant. Great believers are great believers, even if our theologies differ.
I hang out with great Catholics all the time. It's a good thing, not a bad one (and somehow I haven't crossed back over the Tiber yet.)
(/Out of Character)
5) Start living like a Catholic.
This is a good one, and probably the one that will make the biggest impact. Don't worry about those pesky doctrinal concerns. Don't worry about what it does to your marriage or other parts of your life. Don't worry about whether you actually BELIEVE in it.
Just start living like a Catholic. Go to mass every holy day and every week. Pray the Rosary every day. Before long, you will feel like a Catholic!
Of course, this is true of any belief system...if you just start doing it even before you believe it, then eventually your beliefs will come to support your actions. This is basic confirmation bias, and is completely human nature. So take advantage of that. "Fake it till you make it."
6) Give God an inch--but only an inch.
Changing to Catholicism is going to be difficult, so you're going to need to be willing to change some things in your life. Make sure that your denomination is on that list--be willing to allow your denomination to change.
But nothing else--don't let Him take a mile. Because then you might end up reading His Scriptures every day, or even worse! studying them in context, and that can be devastating to your Catholic conversion.
(Out of character)
At this point of Little's list that I found baffling. It seems that he is making the (absurd) statement that if you pray and are open-minded you will end up Catholic!
He says that you should just stop praying altogether if you want to avoid Catholicism. Or if you are praying, you must refuse just arbitrarily.
It is of course extremely obvious that this is untrue. I wouldn't even make this argument for Christianity in general, as prayer is a large part of non-Christian religions as well. To imply that praying will inevitably lead one to Catholicism is silly. Likewise it is silly to claim that everyone who is open-minded ends up Catholic and no one else does.
I can't really lampoon these two because they seem to lampoon themselves.
(/out of character)
So if you can do these things, you too can convert from Protestantism to Catholicism. Read Scott Hahn for the writing and emotion of the story but don't get into the theological details; read medieval church history but ignore the ancient stuff; read Scripture and Church Fathers like they are Catholics rather than Jews; only hang out with Catholics and go to Mass and pray the Rosary every day; and be willing to let God change your denomination but not willing to commit yourself to following what His Scriptures say. Do this, and you too can remain a Catholic.