How can I be useful for the senior developer in my team?

I'm a junior developer and to senior developer I ask questions and do the delegated work. Are there other ways I can be useful to my seniors?

One of my seniors also mentors me I want maintain monthly 1:1s but not sure what to ask him each time.

Ask them directly - there may be some task they could delegate, or something you can include in your workflow in order to simplify theirs.
Also start writing down questions that you come up in between your 1:1 sessions, to ask them during these sessions.

Ask better questions. I don't think the question you asked here is the correct question to ask.

@electrineer Easier said than done. Constructive feedback my friend...

@ScriptCoded that was her own concern, just worded differently

Make yourself useful.

Try to think outside of the box.

Build interdisciplinary knowledge.

Ask about why and how it works.

Don't take things for granted, even if you think you understood them.

One of the most important things:
Read the existing documentation and comoare it to the sourcecode.
If it doesn't match write an update (if its also in sourcecontrol make an new branch for this process) and inform your seniors. If documentation is missing you can create it.
Documentation is never enough and often outdated/missing.

Don’t ask the same question 3 times. I get it. We forget things. But try to remember
Also when asking a question, ask for direction instead of every step on the way.

Never hesitate to ask a question. The more you delay, the more you pay. 😅 As a senior, they got responsibility to clear out your doubts. But, before asking - write them down & do some googling. Writing the questions down will help you to simplify them, as well as help you to find out the answer yourself sometimes.

And, when you got free time, go through their codes, try to think why they choose to code this way and that. Will help you to understand - how they solve a certain problem, the convention they're following. Thus, will help your communication with them.

In all honesty, hard. You need more knowledge and experience to be more useful.

But don't let that discourage you. We've all been there. It's just part of the process.

In the meantime, don't make it harder for yourself. Listen, ask a lot of questions and don't be too smart/stubborn.

Books are always good way of learning new things.