Use a sanding block and some 220 grit sand paper and gently run that across the deck. This will help ensure a nice flat surface for the heads to match up to and will help remove some of the crud that may have built up. For the cylinders I use a rag and solvent.
The head bolts are reusable as long as the threads are not mashed or warped. Just remember that the there are 4 specific bolts for the corners and the 2 in the middle...the 2 middle ones are painted black i believe. Also, look up the torque pattern for the head bolts. If they are not torqued properly you likely have problems in the future.