I was told to tap the bottle on a table a couple time after use. This gets the glue out of the nozzle. So far it works better than not doing that especially when I remember. Also found that you can buy just nozzles so you might check that out. Don't know where you are but Galaxy hobby in Seattle is where I can get them.
I store the bottle upright in a ziploc bag in the 'fridge. Helps keep the nozzle build up soft so a wipe with a paper towel easily clears it off. Always have a piece of .032 wire handy to open the hole too.
Squeeze some air out of the bottle before you turn it to apply the ca. That way, when you turn it upright & let go it will suck air (& adhsesive) back down the tube. But i still keep a small drill bit handy.