Here's a few of mine:
-If using a superior expanding wood glue (ie Gorilla glue), you really only need screws every 5-6 inches. for other glues, 4 is all that is necessary.
-to help avoid cracking, start drilling a minimal 1 inch from the edge. and use a counter-sink of course.
-when trying to make a ported enclosure look nice and sleek, use normal wood glue on the port walls instead of gorilla glue. an expanding glue like gorilla will expand and drip down the sides of the port wall, not making it look clean as possible.
- I like 1.25 inch dry wall screws (#6). make sure you buy a matching counter-sink bit to fit your screw size.
-Buy the hand squezze silicone tubes so its easier to seal those hard spots.