Excellent advice up above, as usual.
As regards publications, try and get hold of a copy of "The Airgun from trigger to target" by Gerald Cardew. This will give you an excellent insight and much of the content is still relevant today.
If you don't have them already, get hold of as many of Jim Tyler's articles on spring gun tuning and experimentation.....Airgun World is the place for those.
Also, if you can get hold of some copies of Sporting Air Rifle magazine, from the mid-80s, Jim Tyler again, they're brilliant, and they do come up for sale sometimes.
Airgun Shooter magazine has a monthly instalment from Lyn Lewington - get as many as you can, it's all about building that "knowledge bank" up.
Earlier issues of that mag had the technical articles written by no other than Steve Pope.....If you go onto the V-Mach website, you can download these articles. Also, whilst there, download the instructions for fitting the V-Mach kits.
Then, we have our very own fantastic resource...Many excellent threads to be dug out, right here on the BBS. And if you google up "blah blah blah model tuning" you'll unearth many informative "how to's".
That little lot should keep you going for a fair few years, matey!
The Inaugural Spring Rifle Gathering at T20's. June 15, 2013.
2014 Boinger Bash, June 7 and 8. Open Airgun Gathering, September 6/7, 2014. Boinger Bonfire Bash Nov 8/9, 2014. 2015 Bash June 6/7.