Create a bike project binder and include the manual and all the receipts as you accumulate them.
Write down or photograph the serial number of the frame and fork and motor.. If stolen it will come in handy.
Print out and read the manual. no kidding!
Find the American distributor phone # of your ebike and register it (don't take the LBS salesman word that he'll take care of it).
If you have a problem you can always call them back.. Has worked for me on several occassions, and they remember who you are.
During the 200 mile tune up ask all the questions you have... you may not see them again! Make sure they check the tightness of all the important bolting and spoke tension.
Before each ride or once a week check the tire pressure.. Max pressure in rear, 20% less in front.
Cleanliness is important to me.. I clean my bike with a Showroom spray that is teflon, repels dirt... And I dont use water.. If you spray with a hose be VERY careful to use the mist setting..
If you have mechanical disc brakes you will need to adjust the pad clearance at least once a month.
Every 300 miles you should be cleaning your chain and recoating.. I use Boeshield T9, which is paraffin based and doesn't accumulate grit. Repalce the chain if it starts slipping.
Every 5oo miles or so you should check tightness on all the important bolting on your bike.. This will take a while the first time.. Hand tighten with your allen wrench and sockets set, or use a small torque wrench and chart if you're really nuts about tightness... just remember you're dealing with aluminum that can easily be stripped. Depending on what you find you may not need to do this again for awhile.
Every 500 miles pull the brake pads and check for wear.. If they are squealing you can sand the pads and the discs then wipe clean.. Rebed the pads by breaking very hard 5x in a row on each brakes. Depending on what you find you many not have to do this again for awhile. Replace the pads if they are less than 25%.. They are cheap on eBay.
Check the tires for rot and wear once a year... If they look at all marginal replace them.. You should get at least 3000 miles from them less if a mountain bike.
If you ride in cold weather or store in cold weather condensation can be a problem.. Try storing the bike in a warm room to drive out the moisture from the connections...
Heres a pretty good general instruction:
http://www.electric-bicycle-guide.com/bicycle-maintenance.html