I want to start a sketchbook (need help)

Maybe take strolls on a local park or other scenic places, and take inspiration from what you see? Alternatively, maybe make things like short comics and fanarts?

Also, not directly related to your question, but keep your older doodles and drawings. Even if future you comes to find them ugly, it would still show you how much you changed.

People on public transport

• Pick 3-5 basic objects, arrange, draw, repeat

• Go to a park/ museum/ mall, choose something cool

• Draw people on the train/ bus (kinda really hard if you're just starting)

• Find month long drawing challenges with prompts (like Inktober)

• Use ai or ask people around you to pick something to draw

• Set alarm, draw the first thing you see when it goes off

• Put your pen to paper and make it move (seriously, don't worry about WHAT to draw, just fucking draw. No think, just draw.)

I would recommend doing some combination of all the things people suggest. That way you can do some experimenting to find what works well for ya, and it helps prevent the burnout of doing the same thing every day. Good luck and remember to have fun!