First and foremost, organize yourself by separating the clothes by age group. Put away the clothes that are too big/small and only put in the dresser the ones he will wear now. Buy some bins and label them by size so you can easily update your dresser every three months as your baby grows into the next age group.
I have a great trick for organizing the drawers that I picked out in Parent's magazine almost 3 years ago.
I put shirts and undershirts in one drawer, pants and jumpers in another (my 2 boys have to share a dresser, so they can't spread out). The trick is how you fold and store. I don't fold the shirts like adult shirts. For my infant, I take the onesies and fold them in half, so that the bottom end w/ snaps meet the shoulder end. Then, I fold in half again at the center so the shoulders meet. I do this with all his shirts. Here is the best trick to see everything, I file them in the drawer, with the sleave end down. I don't stack them. Now, you can see every shirt because they are filed like hanging folders! I do the same for his pants, only I fold them in half lengthwise, then in thirds at the bottom and the knee. This makes a neat bundle than can also be filed, too.
Now, as your child grows, so will his clothes. For my soon to be 3 yr old I also file his clothes, only since he went into 18 month size it was easier to fit shirts in his drawers by folding them in thirds. First, tuck in the sleaves, then fold the shirt like you would a letter. You still retain the width of the shirt, but you just adjust how you file it in the drawer. You can see every one!
Finally, I went to Walmart and bought a few large plastic bins that look like drawers. I keep these in my boys' closet. As they grow out of clothes, I pop them in the drawer in the closet. When the drawer gets full, I go through it and determine what to save, donate, sell, etc.
Best of luck to you!