Don’t worry if it feels like your kit is not complete. This feeling will never go away. In fact if you can always do the best you can with what you have you’ll do just fine.
Here is some info on Macro Photography.
Here is some more info on Neutral Density Filters.
I don’t have any specific plans for a lesson dedicated to storm or lightning photography. To be honest I have concerns about safety. All I can say is you have to be extremely careful. Storm and lightning photography is very dangerous.