One, have at least 8' of copper in 18" coils behind the fridge, to allow you to pull the fridge out without kinking the copper.
Second, whether the supply is a water box set into the wall or you used a self piercing sadle valve in the crawlspace, the copper should be screwed to the baseboard with a clamp to prevent the copper compression fitting from working loose when you move the fridge, and another clamp should be screwed to the refridgerator frame to hold the copper secure to the compression fitting at the valve. (The valve is a solenoid, and will cause a small water hammer if you are trying to trace that sound later...)
The coils should be nice and round, go buy an "imp" tubing cutter (less than $10, lasts forever, and is really handy) to cut the copper with. Use new compression sleeves on both ends, and make sure that if you have a water box that the painter didn't paint all over the threads. If he did, clean the valve with some goof off prior to connection.
Connect the supply end first, then run a gallon or so of water into a bucket to flush the junk out of the valve and copper line before you connect it to the fridge. This is a good time to check the supply valve to make sure it isn't leaking at the valve stem.
After you finish the install, run lots of water through the door if you have a water dispenser to flush the system, and you will want to dump the first 3 tubs of ice for the same reason. Make sure you dump the ice tub completely into your sink every month or so to keep the ice fresh. (It actually will evaporate and absorb odors over time)
Pull the fridge back out after 3 days to check for leaks.
Make sure you protect your floor with a piece of cardboard before you pull the fridge out.