One more thing - don't be afraid to get stuck in and take it to bits - it's the only way to learn really. Buy a haynes manual and you'll find a common faults list in the back with remedies. They're usually rated, so you get an idea of how hard the job will be.
Get a big piece of plain card and write 'front' at one end of it. Everything you take off of the bike, put onto the piece of card in a rough estimation of where it was located on the bike. You could even go so far as to label items.
When and if you have to take the carb to bits, just do it slowly and methodically and you'll be fine. Look for signs of 'gumming' - kind of like a brownish film, around the jet/needle etc. You can buy specific carb cleaner stuff from halfords that'll bring it up like new.
Check and eliminate all the simple things first (like I said above).
Oh - just thought - 1st thing to check - take out the plug and check that to see if its either oily or scorchio brown. Oily = Running too rich. Scorchio = Running lean. The trusty haynes manual will show you how to set the mixture. Could also be a problem with water ingress into the coil/ht lead/plug areas.
DONT spray WD40 onto a hot engine - I found out what happens the hard way
Good luck, keep us posted.
