Photography equipment to use?

I'm a photography student and I shoot anything from weddings to outdoor portraits. I have a few questions about what equipment I should start to invest in. I currently have a Nikon D80, and an off camera flash.

Should I invest in a set of strobes, umbrellas, and light stands? Flashbracket? Or off camera flashes with slaves?

Any advice would be appreciated, I get confused when it comes to slaves, cords, flashes etc. So please be detailed.

I'm just starting out in the world of photography but you'll defiantly need light stands and umbrellas to get a perfect lighting. There's nothing worse than a yellow photo from the unnatural looking light. These instruments should get natural looking lighting. Lighting is everything in photography, it is what it is.

A good extra flash and a self standing umbrella is very important additions to your Nikon.

If you shoot weddings, the very first thing, I would get is a second camera.

If you are shooting weddings as a student with limited experience… I'd be spending money on professional indemnity / accident insurance.