A habit is something that you have learnt to do some time ago and now just happens naturally, like walking or fastening a button on a shirt or SWIMMING. You will all have been though teaching programs, learnt to swim how the teachers showed you and could quite happily swim a load of lengths while singing a song in your head because you don’t have to tell your muscles exactly what to do anymore.
The problem with this is that if you don’t think about improving your techniques all the time they will just stay the same and your improvements will not be as great as they could be.
The great thing about this is that once you have picked up a great habit, it will stick... forever! So if you have good habits you won't go wrong!