ok...i will say i HATE swimming...but i can swim...and i sink!
This happened to me:
we were doing a life saving seesion in physical education once at school - the teacher said "Ok, everyone, roll up tight into a ball, and you will float. If you are ever tired, do this because it doesn't take much energy but it will let you breathe" etc etc.
Everyone in the class does it...everyone floats - except me
i sink...and sink and sink....till i have to 'unball' myself to get a very much needed breath of air.
since i hate swimming so much, and can't really swim very well (eg. i struggle with 25m and get lapped twice over by average speed people...) ill see if i can give you any advice...
1. If you can't float - try under water swimming
(i luv it)
2. start at the shallow end and start walking towards the deep end....i find that you actually start 'floating'...it gets much harder to touch the ground...(or maybe im just too short)
3. do a bomb dive into the deep end - your instincts will probably kick in.
those are the only things i can sort of think of....obviously if you haven't swam before, have a friend or two with you for safety.
good luck!