I tried trading Bitcoin a couple of years ago but quit after I lost $300. What advice do you have for me if I decide to start trading again? Thank you!
Go for bakctests and demo trading
This seems to be a simple and practical, good advice, just what the OP was asking for.
On the other hand, this is not the best place to write this but IMO the best advice for a beginner trader could be not to start trading: I don't believe in TA (I have never worked as a trader professionally but I own a degree in economics) and it is quite possible that you get the same gains by simply hodling, so you'll have much more free time to concentrate in other business, better sleep, better focus, better mood...
It is not for everybody as not everyone is prepared to hodl during a multi-year bear market and I could be wrong if a black swan happened and everything goes to zero, so this shouldn't be taken as a financial advice, but it is my personal choice and I feel happy to share it.