Buy good quality paint like Benjamin Moore Regal Select (aura dries too fast for me). I can’t emphasis this enough! Benjamin Moore is thicker paint so it won’t drip as much and covers well and doesn’t dry to fast so if you paint slow you won’t see the lines where you painted/rolled.

Paint one room at a time. The hardest part honestly is prep work. If you take the time to do it the painting part will be easier.

There are so many YouTube videos. I started watching Vancouver carpenter because he has good tips and is funny at times. He has a lot if videos about repairing drywall, patching, painting, etc.
https://m.youtube.com/watch?v=6noW8bBBh6I

Are there any good Instagram or online resources that can help a novice take on the interior painting of an old house? Walls are dirty and drab and I need some motivation! I have no idea what I’m doing.