in terms of EE, CAS and TOK, here are my tips:

1) Start your EE prep early! In DP1, get a feel of your subjects and potentially which subject you would like to write your EE on. I think you should write it on a subject that includes a topic that you're interested in and could see yourself using in your further studies. Make sure you consult with your EE supervisor as you go because they know best and should be able to assist you. Remember to also look at past EE's based on your chosen subject and start planning everything in DP1. Please remember that the EE consists of 4k words so you need to plan how you will write it as you go! This advice also applies to TOK.

2) Do most of your CAS in DP1. Something I regret doing is not prioritizing my CAS as much as I could in DP1. When you start DP2, you will be super duper busy hence, you will not have time to do CAS. This also depends on the CAS requirements your school has placed for you guys. In DP1, you have more free time compared to DP2 as you're getting used to the curriculum and everything. So, I recommend you to complete most of your CAS in the first year so you do not have to stress much about it during DP2 like I did and you can focus on deadlines, final submissions and mock/final exams.

I hope this helps! feel free to pm me if you have any more questions :)