I simply read up on some- and listened to what people were saying. After a while, the more people I got to know within "the" typology community the more people told me "You don't really sound like an INFP at all," especially after they saw my video (yeah, I got one of those, but I haven't showed it to anyone here on personalitycafe), they said I was definitely an INFJ.
In my opinion you should check up on your cognitive functions. I was surprised when I saw my cognitive functions setup, because it typed me as INFJ/ISFJ/INTJ even though MBTI tests always typed me as INFP (sometimes INTJ). I think a lot of these tests can end up showing the ideal you mixed up with a bit of "real" you.
We'll also have to remember that, for us who are bipolar (in case you are), we tend to get different results (more often than anyone else) depending on our current condition as we take the test. I took one of these tests right now and it showed me as ISFP.
Ps. I just woke up so this post probably doesn't make any sense.