After the first 3 days you will be able to think again. your first thought will be,WHAT THE HAVE I DONE! the remainder of the first 2 weeks is still very hard, but at least you will be able to get some sleep. It does keep getting a little better each week.
How you prepare is simple. do not ask any questions unless asked to. Do not talk back.
I could give you a long list of does and don'ts, but it would not help you much. If your Drill instructure feels that you think you know it all, it would not go well for you.
You will HAT your DI. He is one mean s.o.b. but when he is done with you, you will be one of the few, the proud, a Marine. You will always a marine. Long after you are out of the corps.