Assuming you have auto battery 510 used with atty + cart - various upgrades
1. MANUAL
batteries! Safer from leaks, easier to get a good hit
2. LONGER manual
batteries - Joye 510 mega xl manual
batteries (128mm long w/ a carto but 60-70% more charge than standard 510)
3. Cartomizers! Boge standard resistance cartos (slim ecigs cannot use the hotter low resistance cartos or attys). Put your fave juices in cartomizers, the most popular way to vape. I find thin 920% Vg or less) juices that are light and clear (leave little flavoring residue) keep a carto working well longer.
4. Go to fat battery 510 - either Ego or its popular clone Riva 510 (and I recommend Liberty-Flights.com and press the 20% off on upper left front page). This will give you 650mah or higher battery charge and the option to use hotter LR attys and cartos
5. various shape 510-threaded 3.7v mods and variable voltage devices
I use standard Boge cartos - my Riva 510 vapes a bit warmer than 510 and I can share the standard Boges w/ my slim 510 manuals. Many prefer the hotter LR 2.0 Boge cartos which can only be used on the fat battery models. There are more exotic cartos too like reservoir ones and clear ones (that can crack and fall apart but some like them)
Note - fat battery models and mods w/ 510 threads can use any of your slim 510's atomizers/cartomizers. The fat/mod models use their own faster chargers that can damage the slim 510's. And the fat/mod models can use the hotter LR attys/cartos which use charge up faster and can damage slim batteries.