Okay, I think the "unconvincing" was me, so I'll bite. First, what are you using for drums?
For me, there are two main issues (and both are big)
1) Does the "hit" itself sound real?
In other words, is it an electronic synthesis of a drum sound, or is it a real recorded drum? Assuming it's a real sample, is it a good one?
2) When the "hits" are combined in your drum track, does it sound real?
Here, real means human. Is there some variety in the velocity, or is every hit exactly the same? Are rolls, fills and accents present but varied? No fills at all--or the same fill over and over again is a dead giveaway. Is the timing too perfect? Or is it "humanized" ever so slightly?
Now assuming those are covered, you have to deal with how the drums sit in the mix. Obviously this deals with volume, EQ & compression. All of these are easier to tweak if you have separate tracks for kick, snare, toms, OHs, etc. More on this later (and hopefully from some others, too). In the meantime, tell us what you're using for drums and how much editing capability you have.