Generally most prefilled cartridges that come with kits pretty much suck. I dont know what your are but some come prefillled with juice that is 100% PG, which might give decent flavor, but provides very little vapor. When I got my E-Power, the 5 prefilled cartridges went right in the trash, I didnt even open them. Also cartridges are inconsistant and will randomly dump half the juice into your mouth. I would def get some cartomizers. That will allow you to fill your own and use any juice and ratio you like. Cartos are alot more consistant and hold a lot more juice so you dont have to refill constantly.
I would get some Boge cartos to start. They are popular and work well. Many vendors sell them and most have 2.0ohm and 3.0ohm Boges. While most people prefer the 2.0ohm Boges, they are low resistance, and like I and others stated above, low resistances are only for bigger battery PVs. Since you have a slim ecig, youll want to get the 3.0ohm ones. I would get them from Crystal Clear Vaping because they have free shipping and good prices, and the carry the 2.0 and 3.0ohm Boges, but like I said, many other vendors carry them too. The are easy to use and will be easier to learn on bc they are regular size cartos. CCV gives you a free syringe with all carto purchases, which you could use to fill them, but you can also fill them with the condom method or just dripping into the top. I use a syringe to fill all my cartos because its quick and very easy to do, and also bc I use CCV's Ressurector cartos which hold almost twice as much juice as the Boges. A syringe takes the guess-work out of filling and ensures they are filled correctly, but you can fill them any way youd like. If you do drip fill, make sure you give the juice time to settle to the bottom and wet the atty or you could singe the wick bc the attys dry and ruin a carto, plus get a nasty burnt taste. Also what ratio is the juice you ordered? Generally, higher VG, thick juices will clog a carto faster and dont wick as well. Thats why I recommend using 30% VG or less because it works better in cartos and will help them last longer.
I think you will really like cartos a lot more than an atty and cartridge like you are using now. Just remember to keep them wet and refill before they get too dry and I think they will def make your vaping experience alot better.
Goodluck!
And agree... its gotta be Dr P 
