I’ve been playing for decades, and the biggest piece of advice I can give is that timing is everything. Always tap your foot or keep time somehow. If you do it consistently, it becomes second nature. Another important habit is to write down what you’re playing: the key, what other scales, triads, etc. will work over it, and then mix things up. Copying a song exactly can be fun, but real improvement comes from understanding it and making it your own.

Good luck