When I got my C I made sure to get 20 new caps for the
tanks as I've heard that after many insert/removals you need to replace the cap to keep it from leaking. I also ordered 5 more empty tanks. Always order extra's as you never know when you will need them and haven't a non-working e-cig sucks because you didn't spend the extra 5 bucks for tanks/caps.
The C comes with five atomizers so you really shouldn't need more of those for at least a month. One thing you will want to do is after opening the atomizer, blow out the PG that is in it. Just put a kleenex or paper towel around the end with the needle (the part that goes in to the tank) and blow in where it connects to the base.
When you put on a new tank do a couple of dry draws (don't press the button). This will let the liquid flow down the needle a bit and will help with dry burnt tastes. After drawing on it you should see small bubbles go to the top of the tank. This tells you it's wicking properly. If you don't see the liquid level dropping then it's not wicking and you will eventually get a dry hit (burnt taste). If you see a bunch of bubbles and your not drawing on it then it's leaking. You'll want to take the tank off and see what's happening. Although I have never had this happen with my C yet.
One finally thing. The part of the tank that you put your mouth on has a small hole in it. You can use a paper clip to remove this. Then down in side a bit farther there is another small part with a hole in it. You can remove this part also. As you use it you will see some condensation collecting. I usually pop these out and run some water through it to wash it out. I also usually leave out the second part with a small hole as I find it restricts vapor flow a bit to much and can cause condensation.
Hope these tips help.