[Starting with A 7 RIII and fashion photography]

I'm a photography enthusiast and use A &R III. 

What are the best ways to learn fashion photography and the must-have lenses required for fashion photography?

 

Thanks!

[Sony a R III to A1]

I'm a photography and video-making enthusiast. 

Given an opportunity, should I upgrade to Alpha 1 or use the A RIII till I get more skilled?

Thanks in advance for your advice!