Once you have identified your plant (learned its Latin name, genus and species), do a search on the Internet. Specify what you want to do, i.e., pruning, fertilizing, propagating or whatever. This will make the search more confined. Usually within the first 10 websites will be a site that will give you the information you want.
I have a shelf of gardening books wider than my arms can spread and use them less than half of the time for reference. The rest of my research is online.
Here are the pruning basics to get you started.
1. Keep your tools clean, sharp and oiled.
2. Own the best tools.
3. Stand back and think before you prune: What do I want this to look like when finished?
4. Cut the worst first: dead and crossing branches, stubs and unnecessary excess.
5. Be bold, but do it gradually.
6. Periodically clear away the debris and look at your work.
7. If in doubt, take a break and don't cut the branch.
8. Call for help if you feel you're over your head, then watch and learn.
9. Use the appropriate tool for the job. Don't use a chain saw on a rosebush.
10. Fertilize with the appropriate fertilizer in the appropriate amounts after pruning, water it in and enjoy your work as your plants respond with a new growth and vigor.