Don't panic
(Corny may I sound) it's not the outcome that matters! You must go and "have fun" because it's a very good experience..
Besides, you've already paid for it, at least you must go and waste some of the chemicals you've paid for and watch pretty colour changes
I'm pretty sure that you don't need to practise unless you can't do the following:
- read the graduation on buretts/pipettes
- fill pipettes/burettes properly
- write and balance simple chemical equations
- gyrate your hand to the point where it's about to fall off
well, it's a good idea to do *some* practise titration questions that have lots and lots of calculations involved, because the most daunting thing, as you will find (if you go), is NOT the actual titration but the calculations. (Unless you're going in for fame and glory
then you will need lots of practise on the actual thing as well - i.e. ignore your friends and disappear to the lab during lunchtimes. Well.. and a tiny bit of luck but I'm not going to elaborate on that..)
Just go!