You can block any knitted or crocheted fabric as long as you have a tape measure and a large, flat surface on which to spread out your pieces, such as a bed or a spot on the floor that pets or children won't disturb. But whether you wet block or steam your pieces, you'll find the job more pleasant — and get better results — if you invest in some blocking equipment.
A large, flat, preferably padded surface for laying out your pieces: It should be at least a little larger than the knitted piece itself. Many knitting stores sell boards specifically for blocking, but you also can find directions online that show you how to make your own. Just type "knitting blocking board" or something similar into your favorite search engine.
Blocking wires: You can block your pieces without these, but you'll have much nicer results if you invest in a set.
Pins (preferably T-pins): They hold your knitted fabric to the blocking board. Don't use pins with colorful plastic heads because the steam will melt them.
A tape measure: After all the trouble you went to knitting to gauge and specific measurements, you want to block your pieces to the correct size, don't you? (We hope the answer is yes!)
A steam iron or spray bottle for water: This gets your knitted piece wet.
A large towel if you're wet blocking: Loosely rolling your knitted piece in a towel removes some of the water.
Schematic drawings of your pieces: These help you determine the exact shape you need.