There are a number of guides out there on rebuilding EVOD coils that could explain how to do it better than what I can provide here. For instance, the videos are the best guide. If you want to rebuild an EVOD coil, try searching on youtube for an instructional.
Assuming you have the right supplies (organic cotton, kanthal wire, ohm tester etc), then you will be able to begin rebuilding it. When I first began to rebuild my coils, I ran into a few problems that even the guides and videos didn't talk about. I'm going to describe them here.
1. Make sure the coil is not touching ANY metal at all. The bottom rubber part needs to be clipped properly, but the coil itself also need to be avoiding any part of the metal sides. This can be frustrating when you first begin rebuilding your coils. So remember to avoid the coil from touching any metal.
2. Instead of rebuilding your coil all the time, you can also just yank out the organic cotton wick and burn the bare coil, then re-insert another cotton wick.
3. I have found a smaller coil to be better, meaning it is wound around a thinner piece of material (nail, hex key etc). This makes for an easier build in general.
4. Buy enough kanthal wire. The wicks or cotton will last a long time, but the kanthal wire can go quick especially when you are first starting since you will waste some trying to get your first coil going.
Kanger Protank 2
One of the downsides of this tank is that the flavor doesn't taste as full as other tanks. I don't taste the full flavor of the e-liquid I am vaping. Additionally, you may need to buy a Kanger airflow valve for it, because the airflow in the protank 2 doesn't work too well. I bought one myself, and it works great. The airflow valve only costs around $8 or less.
This tank is a solid-built glass pyrex tank that can handle almost all type of e-liquid. You can also use standard EVOD coils with it, which is a bonus. Overall I would rank this tank pretty highly, because it is durably built and aesthetically attractive for a reasonable price. It can be used with a 510 battery.
Kanger Airflow Control Valve
Since then I have bought several more kits of other brands, but I have found the basic EVOD kit to be my favorite of the basic e-cig kits out there. Flavors taste good and it is reliable. You can buy cheap replacement coils at many websites and e-cigarette retailers.
The EVOD allows for easy maintenance as well. For instance, burning the coils to clean gunk off the EVOD is easy. It is also not that hard to do EVOD rebuilds if you have the right equipment like kanthal wire, organic cotton and an OHM tester.
A downside to the basic EVOD clearomizer is that it is a plastic tank which means that certain liquids can cause it to crack, but most retailers will tell you if their e-liquid is known to crack glass tanks. Overall I would rate Kanger EVOD the best of the low price e-cig kits.