1. Get a good "big battery" device.. whether it is a 1000mAh ego or some kind of box mod, get a good one.. put some extra cash down to get one of these.
2. Get backups!! Atties (or cartos), batteries and juice.. ALWAYS have more than you need.
3. Get a mixture of atties and cartos, some days atties will keep you going and on other days you really need a bigger punch in the throat; I find cartos in general give a bigger throat hit overall.
4. Get a realistic strength of nicotine to begin with. If you happily vape 18mg, buy some 36mg unflavoured as a backup.. there might be a handful of days when you need to knock it up a notch (to 20mg.. or 24mg.. or something) to see you through.
5. Get tobacco flavours, at least 2, even if you don't "like" them for a daily vape. The reason being is that sometimes you just crave the disgusting flavour of tobacco.. you might only vape it for 30mins.. but it will satisfy that craving.
I'm sure there are more.. but there is 5 things I could think of off the top of my head.