my ib tips (as an ib year 1 survivor)
Do your research the summer before year 1, find out what unis want and adjust your subjects accordingly (this mainly applies to HL AA, but a lot of engineering programs will want chemistry along with physics).
Contradiction to my last point, but go off of subjects you're at least confident in, and that you enjoy (i.e. if you suck at physics, don't take it, even if you want to do something physics related, it'll just be hellish)
Don't let what you think you want to do in the future limit your choices. Sure, it's good to keep it in mind, but people change, so it is more important to take subjects you want to study rather than what you need for a career you think you want.
Start thinking about your EE early, and try to talk to your subject teacher (there is a large chance they will be your supervisor, and if not, it's still good to get an idea of what is expected of you).
SPACE.OUT.YOUR.IAS!!! My school does this for us, but it's better to do your ias during your first year and one at a time rather than cramming them all in year 2.
On a similar note, get your CAS done as soon as possible (forgot this one as I've already done it), it takes such a massive load from your shoulders going into year 2.
Get as much feedback from your teachers as you can!! It can be hard to hear critiques of your work, but trust me, it'll help you a lot in the long run.
Continue with your extracurriculars, I know a lot of people will quit or limit their ECs during the IB, but imo, there's nothing worse you can do. ECs keep you grounded and help you focus on stuff that isn't the ib.
Don't be afraid to switch subjects/levels, if you find out something isn't working for you, it's always easier to switch than to tough it out, trust me, your future self will thank you!
Don't take it too seriously, sure, it determines your future, but you also need to chill the hell out, because the only person your stress is hurting is you.
The IB is only as hard as you make it!
Good luck! Feel free to ask me anything in the submission box on my profile!
-kat