Okay, it's important to know that in the RP lightning is not strong against water, but they are good for combinations. If a lightning technique clashes with a water technique with an equal power, they will cancel each other out and the lightning won't continue. But if lightning clashes with earth with an equal power, the lightning will continue in a weaker state.
It's important to understand Raiton first.
Lightning is electricity, and that is the flow of electrical charge, electrons. Electrons exist in everything around is and it keeps all the matter bound together. You could say that in the Narutoverse they use chakra to move electrical charge. so the chakra basically works like voltage.
Lightning is a nice element in the RP. It's good for both attacking and defending. An important aspect of lightning, is that it contains piercing/slicing power. You can use lightning to increase the slicing power of weapons etc.
Many lightning techniques have an instantaneous effect, which means that most of the lightning techniques disappear when you stop channelling your chakra into them. So if you suddenly perform a wind technique, the lightning stream will be gone. However, if you create i.e. an earth pillar, it won't disappear after you perform another technique. Furthermore, lightning release is the fastest elements, but doesn't move as fast as actual lightning in real life.
____
Why do you want to learn lightning?