Looking for some advice
Does anyone do freelance work on the side? If so how did you get the work? Whats it like freelancing?
I'm looking to try and earn some extra cash

Get a portfolio with work that you have done up

@benleah did you have to invest into marketing at any point? like faceboom ads and such

Structure you business properly. You will have deductions...
Read a book or two on marketing and sales. Get referrals.
I agree, do not undercharge! If fixed project bill and get paid 1/3 1/3 1/3.
Keep asking questions.

One thing I would suggest (depending on what sort of freelance workhouse are doing), is making a portfolio website.

If you are a web developer and write your own site, that website is a show piece in itself.

Even if you can't make websites, get together some previous work and use a website maker service to put it out there.

This makes you a much more favourable hire to a prospective freelance customer!

@benleah I couldnt agree more with your thoughts on charging what you are worth. There is a line where if you charge too little they dont take you seriously and think they run the show. As far as charging by the day though, that I disagree with. Too easy for a client to say you are milking it and overcharging. I always charge a fixed price with the understanding that addional requests or excessive modification requests incurs additional charges.