My tip is to not be afraid to go back to basics. I have been using Vera for a few years now, and was starting to have issues with luup restarting on a frequent basis. This meant that sometimes there would be no response to commands as it was restarting. I made a backup (always make a backup!) and then cleared out all the apps I was no longer using. I then got rid of the apps I didn't really need but had been playing with for a while.
A full wipe may have been better, but this seems to have resulted in a similar outcome without the pain of removing & adding back in all my zwave devices. My system is nice and stable again. I'll now - slowly - add in the non-essential apps and monitor to make sure they don't impact on reliability.