Despite all of its complexities, electrophysiology can really be boiled down to two equations (Nernst and chord-conductance). I think it's important to focus on one ion at a time so as to avoid confusing yourself.
As far as v-gated ion channels go, for all practical purposes you just need to know that there is a voltage sensor on the protein that induces a conformational change when a threshold potential is reached (though that's not technically correct) and there is a time-sensitive domain that automatically reverts to the more stable conformation after a finite period of activation. The exact mechanism varies depending on the particular channel so it's difficult to make any generalizations beyond that.
Are there any particular topics that are confusing you? (ie saltatory conduction, NMJ excitation, cardiac conduction system)
