Streamlining will gain you metres every start and turn
Bad habits are hard to break - make sure you get into good ones
Flexibility is crucial for swimming - keep supple with lots of stretching before swimming
Don't breathe for two strokes at least out of a tumble - you will lose speed
Make sure you keep your head still in backstroke and only roll your shoulders
If you slip on backstroke starts, try putting one foot slightly lower than the other
Make sure you get into a good streamlined position after the start and every turn
On the blocks make sure your weight is forward on your toes - not on your heels
Try pointing your thumb out from your hand in front crawl - your hand will be flatter
In front and back crawl, don't place your hands across your body centre line at entry
In front crawl make sure you pull all the way down to your hips - don't let the water go
In Breaststroke, keep your head at a 45 degree angle rather than looking forward or down
When kicking off the wall make sure your fly kicks are fast and small or you will lose streamline
When breathing in fly push your chin forwards rather than lifting your head - you will stay flatter
In fly make sure you drive forwards not upwards - lifting too far out of the water wastes energy
On backstroke starts, throw your arms out horizontally around your body rather than straight back over your head