Tip: For many years, decades even, I thought I was bad at soldering. Sure, I got things done, but it was time consuming and ugly.
Then I bought a quality soldering station, and it was like night and day - I had my suspicions since I somehow did a better soldering job at work than at home.
Then I got myself a Weller WE 1010 and concluded that I wasn’t the problem. My solder joints come out so much better now. Oh, and of course, use solder flux.
Oh, and another tip: 3D printer is a really nice tool to have if you’re into electronics. The amount of stuff you can build suddenly seems unlimited.
Maritime electronics, mostly. Autopilots, radars, echosounders, etc. Plus interfacing radios with positioning systems.