Agree with what Henward has said, a small amount of salt with every waterchange won't hurt (although I don't usually bother).
Set the temp of you tank at around 28-30C, certainly invest in a second heater if your current one is letting the temp drop to 245C. pH somewhere below 7, plenty of hiding spots so they feel secure when moved in. Trying to minimise the stress of moving them is paramount. Check the parameters of the water they are coming from, and try to avoid a big swing in pH when moving them. If you're ordering them from the LFS then pick them up when they come in so they don't have to be acclimatised to the shops tank then shifted again soon after. Keep the water clean (frequent water changes) and if you're really keen/worried running a UV steriliser will help, although they can be expensive.
And most importantly, quarantine ANY new additions, fish or plants!!