Care Tips?

Hi I plan on getting a new gecko or 2 but would like to know of any tips you may have to ensure a long and happy life (I've had one before but he died)

Oh and just curious on something for fun, is it ok to put him in the bath tub with a little bit of water and let them swim? Would they swim? 

If they were to mate would they mate for life?

Any other tips and suggestions please let me know!