It's so hard to know any specific advice but I'd say when you're getting into gardening plant more than you need and try different things - ideally write on labels what you're doing with that one, like try some in bigger pots, different soil, more light or shade, different pruning styles or planting times. It's fun and a great way to get a feel for your plants, instead of thinking 'oh this plant is rubbish' try to come at it more like 'oh that's what happens to a tomato without enough light'

Also YouTube is full of great gardening videos, the lesson type ones get boring once you know what they're going to say but watching people show you their garden and talk you though everything and how it's been growing, what they've done too it and etc can be endlessly fascinating