You have made a wise choice. Once I started dripping all my other atty's took a rest. As far as battery life goes it depends on the ohms and amount of use.
As far as dripping w/ RDA's goes.
For a starter just go to fasttech and get your self a good quality clone mech(chi you clone, k100 ect...), RDA (trident clone), a few 18650's, a good fast charger, some silica, ecowool, or cotton for the wick (Silica and Ecowool are easier to start with, a roll of 28 and 30 gauge Kanthal and you should be good to start. You will also need a butane torch of some sort a cheap jet butane refillable lighter can also work all the way up to a fancy 50 dollar torch. Personally I just use a bernzomatic mini torch which is hand held and refillable.
For understanding more about coils, how to build them, ohms ect I'd check out the
Rebuildable Atomizer section and go from there. As a basic rule of thumb the lower the gauge of the kanthal the lower the resistance or ohms. The higher the gauge of the kanthal the thinner the wire and higher the resistance/ohms. Lower ohms drains more amps from your battery but many like it due to the vapor production it can produce. Keep in mind though there are also 1.5ohm microcoil builds doing some amazing vaping as well so really you just need to tinker w/ it to find your sweet spot. I also advised the trident clone due to you not having to drill out the air holes as its adjustable on airholes.
Also another rule of thumb. A dual coil will effectively half your ohm's as in a single coil at 1 ohm in dual coil will get you around .5 ohms.
I started on cartos and used the pro-tanks ect as well as genesis and prefer dripping over all the others.