I would say: "When in Rome, do as Romans do" it's your first day, you don't wanna be the focus of attention, I would prefer to be quieter and observer of the routine your coworkers have. Always be polite, never assume always ask, find an ally and last but certainly not least as in any relationship you're new, don't try to bring on your past experience it's something new you should treat it and enjoy as is and never impose your ideas on your first day, this was the hardest to me

A good read - randsinrepose.com/archives/ninety-days

Generally... observe a lot, ask questions, take notes, learn names, remember you're learning both the direct technical/work stuff and the social stuff.

If they don't brief you, ask... what is the onboarding process? are there formal induction tasks to do? Some places are really organised, others are not; if you have a disorganised place, it doesn't hurt to ask specific things like who can walk you through the code base, who is best to explain the team workflow, etc. You can create your own onboarding.

Generally when you're new, take whatever social openings present as well. If people invite you along to lunch, coffee, etc - good chance to get to know them in an informal setting.

But basically the Rands post covers it all ;)

Congratulations for the day. My suggestion to you e.g Do mistake but never repeat again.

1. Don't leave before everyone else does. Of course, reach on time.
2. Figure out the routine of your colleagues and try to gauge what's acceptable and what's not.
3. Most importantly, ask a lot of questions to either your colleagues or your boss, could be about the code, the product or any other thing.
4. Keep a tab on pull requests/code merges being made right from the first day, even if you don't understand them, glance through them. Code bases are complex, so you can start asking about how to understand the coding style.
5. If you're provided with a machine, try to set up the dev environment right on day 1. You can focus on code from day 2 and try to ship something small within the first weekend. Good luck!

just enjoy the moment

Speak to your new colleagues, don't be shy! Show your interest in what the company and its employees are doing. Ask lots of questions. Have fun learning your new company's ins and outs!

1. Dress well - even if it's a hoodie and sandal type office, wear a button down and jeans the first day
2. Pay attention to tax forms, direct deposit, etc... - if you have questions, ask
3. Try to be social - shake hands, try to remember names - the old repeat their name after they say it trick helps - ie: "Nice to meet you, Joe / Jane".
4. Bring a lunch if one isn't previously planned
5. I wouldn't bring family pictures or fidget spinners or fancy coffee mugs or potted plants on the first day. See how others have desks / cubes / offices decorated and do that stuff on day 2 or 3
6. Go easy on the coffee if you drink coffee. Some drink a pot a day; maybe have just 1 or 2 if it's provided, lol... Or - bring your own if you need it (again, get the lay of the land first day). Conversely, go easy on the water. You don't want to be running to the bathroom every hour, haha.
7. Be attentive - listen when people talk to you; if theres training, try to stay focused and sharp
8. Your first day, your learning. Don't put down how people do stuff, don't suggest redoing X or they should use X instead of Y.
9. Stay calm and good luck!

go to eat with your boss