The more you understand about the way your bike works, the more comfortable you feel riding it, tinkering with it, and upgrading it where you want to.
There are loads of options of varying expense and time demand. You could start by just picking up a copy of a guide such as the famous “Park Tool Big Blue Bike Repair Book”, and a bool like this will be a great go-to next time your bike starts making a funny sqweak or groan.
If you’re able to give up a little more time, you could pop to a local bike shop or try an Evans Cycles FixIt! Class in any of their stores for a basic run down of some common bike ailments and their fixes.
If you want a really in-depth knowledge and even a qualification, organisations such as Cycle Training UK offer a range of courses.