There are basic car maintenance night classes given by many colleges,so check for one in your area.This would give you a good grounding and give you a little more confidence.
There is absolutely no reason why anyone with a little common sense can't carry out basic servicing.Changing air filters,pollen filters,
and filter and spark plugs etc is usually straight foward and you can save yourself a packet.As long as you keep a detailed log of everything you do and the mileage/date that it's done,I can't see it effecting the value of the car too much.In any case,you'll be saving yourself money by doing the work yourself and this will more than balance out any small loss in value.
One thing to bear in mind is that warranties will be effected by not having any work done at a vat registered garage,but if your car is out of warranty(either a manufacturers one or an aftermarket one) then you'll be fine.If your short on time,there is no reason why you can't do an
and filter change one weekend,and then change the air filter the next(and so on).If you have a mechanic in the family or as a friend,get them to help you out to start with and ask them lots of questions.Most mechanics will do work on the side for a few beer vouchers.....
Good luck and if you ever get stuck or need help,you know where we are!