Make it easy on yourself and take out the distributor. Just mark where the rotor was sitting so when you put it back in it is in the same spot.
Cover the hole from the distributor and the intake ports, along with the water passages in the heads, with rags. (that way you don't get anything in them)
I always tape off the top of the lower intake when I pull the upper off just to make sure nothing drops into the heads. Same when putting the lower on. I tape off the holes with masking tape until I am ready to put the upper back on.
Use a rag in the lifter valley and tuck it around the pushrods when cleaning the gasket material off of the heads and block to catch debris. Take your time when cleaning off the old gasket material as it is important to make the surface as clean as possible. I like to use a scour disk to clean the heads and block.
Most auto parts stores carry scour disk pads that you can hook up to a drill or die grinder to clean the surfaces. Then I like to use a little brake cleaner on a rag to clean the metal before putting on the new gaskets.
DO NOT USE A WIRE WHEEL TO CLEAN THE OLD GASKETS OFF! I have seen peices of wire end up in the oil pump and lock it up.
Speaking of gaskets. I like to use Felpro 1250's or similar with a Printo-Seal. They are MUCH easier to remove and clean if you are planning to upgrade heads later or ever have to pull the intake off again.
I like to use a very small amount of Blue RTV around the water ports spread out with my finger. Just enough to fill in the imperfections in the metal. VERY LITTLE. I know it might not be needed but I use it just as an extra measure.
It is a good idea to get new O-rings for your injectors if they are old now and replace them.
Also it is a good time to replace your thermostat and gasket as it will have to be switched over to the new intake.
Follow the torque sequence and go over the sequence a few times as you will see the inner most bolts will have to be tightened some more. Do this until all the bolts are the same ft lbs.
If I think of anything else I will just add on but this should help you some.
Good Luck,
Kevin