You probably won't know what you want to make or even what you can make for a good while. But at some point, you will come up with an idea. Something you would like to see made more than anything. At that point, just start programming. Your first few projects won't be pretty, but nobody ever starts perfect. A lot of projects won't get done either, whether it be lack of drive or shoddy, unreadable coding. This, again, is perfectly natural. You learn a lot of new things with every project, and the next thing you make will be even better than the last. Once you get the hang of things, the only way is up!
As for suggestions for where to start...
- The built-in help menus are your best friend. There's a question mark button on the top right of the keyboard. Whenever you type out a command, it gives you documentation on how it works.
- DEF blocks are crucial to making a project that is easy to read. They make coding modular, which is a major plus for larger projects. I recommend learning them early.
- Arrays are also one of those crucial elements to learn. They let you store lots of data in an index, and have more uses than you'll ever realize.
- Try to avoid using GOTO. We're past that. It makes coding a headache.
- That being said, @labels have other uses outside of simple GOTOs and GOSUBs. The ON GOTO/GOSUB function is very similar to a switch case (if you're familiar with it)
- camelCase is veeeery handy. Don't just type everything in ALL CAPS because you don't feel like pressing the tiny caps lock/shift key on the ever so tiny keyboard. Your future self will thank you for the readability.
- Be consistent! I have a personal ruleset for typing where I use all caps for built-in commands (also called reserved words), camelCase for all variables and arrays, and CapitalizeFirstLetters for DEF block calls. Find what suits you, and stick to it!