Seek a bike maintenance course, Edinburgh Bike Cooperative (the shop chain) do them & female specific events if that is an issue, local city cycling groups may do workshop sessions &/or tool hire with friendly advice thrown in, the local council or transport executive will run them too.
You can pick your level and have guided hands on tuition for a few tenners.
Youtube is also your friend - plenty of how to vids from companies and individuals. Have a google for Park Tools, they have a comprehensive and v good tech section. When you're feeling a bit more confident have a look online for Sheldon Brown's site.
You can either practice on your own pride and joy or maybe hunt Gumtree or the local free ads for a dirt cheap beaten up bike that you can use as your guinea pig without worrying about hurting the one you love
. Simple things to practice like Chains, cables, brake blocks can be got from Asda for a few quid. You never know you could fettle up a nice usable runabout for peanuts and a wealth of experience to keep you away from snotty bike shop snobbery.
I'd also shop around for a nicer bike shop to be your local one, there are some lovely people with a yen for bikes. I only know Edinburgh as a tourist tho so no local recommendations, sorry.