Buy lots when possible and sell singles when possible.  Give up the 1 card that people are overpaying for at the moment to get the 3 that you have been wanting for awhile.

Thanks for the advice. I am def one of those collectors that want to own everything. i dont play on selling much but either way it is fun doing this.

I think locating what you want is about knowing why you are collecting.   There are usually 2 camps.   Collectors who just want to own what they buy and then there are investors trying to buy low and sell high.  
The best advice I can give is to take your time, ask lots of questions and don't bid on emotion.   That will save you tons.   

So I just started collecting MMA cards cause I am a huge fan of MMA. I went to UFC 94 last year and that was the best time I have ever had. I have only been collecting for about a week but have all the ufc, wec, and debut cards. I do have a couple autos and relics too but wan to further my way into knowing the best way to find other memberable cards. I know it is not going to be simple but want to just know what others are doing...