Question about surface preparation for laying kitchen tile.?

I recently removed and installed new 1/4inch plywood in our kitchen floor. We have already purchased enough self-sticking 1foot square vinyl floor tiles to cover the area. The question is, is there any sort of surface preparation to do before we lay them down? I have had people tell me about filling in the seams if they are more than 1/4 inch wide between plywood boards. Also, does the adhesive on the tiles stick to plywood well? Or should adhesive be applied in addition?