There's a YouTube channel I use a lot called "Zeil Learnings". She makes great, short tutorials for using RenPy and covers one topic per video. The main thing I'd recommend is trying out RenPy yourself to get familiar with it. When you download RenPy, there's a tutorial game preloaded into it where you can examine the structure of the game, menus, backgrounds, and sprites. It gives you a good idea about how you call these objects out in the code and how to display them properly. You don't need to know RenPy inside and out before you start working with it. Just download it, open it, and start putting your script into it! See what happens. You'll make some mistakes, but you'll learn a ton. You'll learn by doing :3.

One of my weak points is budgeting... at first, I just threw whatever money my artists needed at them 😅. I wouldn't recommend doing this because it definitely isn't sustainable. But what I would recommend is evaluating how much money each month you can take from your income and put into your game and start budgeting based on that. You'll be less likely to go broke if you budget based on your monthly income instead having a large fixed number. You also should be looking at every way you can save money by giving yourself more work. For example, I save a lot of money by cleverly reusing assets. I'll take some clothes drawn for character sprites and then use photopea to resize, recolor, and reshape the garments to work for other characters.