Replace the O-rings on the end of the oil pipes with new ones.
Install the oil pipes. The hold down screw just needs to be slightly snug. (It will be tight again on the next valve adjustment, after going through all the heat cycles)
Install new spark plugs.
There are two knock pins (guide pins) you need to locate and make sure haven't been lost.
Here is one in place in the valve cover. A loose one at the bottom of the picture next to a penny for size reference.
This is where they go in the head.
Since they are loose, they could come out during disassembly and fall into the crankcase. So make sure you have located these before installing the valve cover. If you wanted to, you could put them in place in the valve cover with a little dab of JB weld to insure they wont drop in the crankcase the next time you remove the valve cover. If you do want to use the JB weld, I would suggest using it on the cover side. Keeping them in the cover side would also help aid in keeping the valve cover gasket in place during installation.
Clean the valve cover gasket mating surfaces.
You will need to apply some RTV sealant to the areas where the gasket dips.
I just apply it to the outside area as to not get excess in the valve train.
Install the gasket in place on the cover. You can usually reuse the old gasket about 6 times before replacing. Once the groove of the gasket is in the cover, you should be able to hold the cover right side up with the gasket on the bottom, and it should hold in place. If it doesn't that could be an indication that you need a new gasket. Although it could still easily fall out of place while installing the cover.
If you are not using JB weld (or something similar) on the knock pins, place them on the head and not in the cover.
Install the cover. The cover bolts just need to be slightly snug. You will feel them bottom out when tightening them. If when tightening the cover bolts, you don't feel the gasket compressing before the bolts bottom out, this would be an indication that you need a new gasket. It maybe alright to try using it this one last time, but should have a new one on hand for the next valve adjustment. Or if you just wanted to be safe, you could replace with a new one now.