Glad you asked, Sam!
I have many things to say about freelancing. Before I get into it though, I’d just like to say that the below has worked for me, there’s no saying it’s the right way to do things. It could have all been an accident. So, in no particular order…
Have a (proper) website
Seems obvious, but these days, it’s kind of integral to a freelancers life.
Lets imaging you’re looking for a designer. You ask on a social network for peoples names. You check a few out and see a couple you like on Behance or Dribbble. Chances are, you’ll pick the person who looks like they’ve been around longer, has set up their business properly. Even having a white-label site from a service like Behance is fine, so long as it’s your own domain (like mine, a proper .com) you’ll look more professional than most people out there.
Sensible communication channels
Following on from having a proper domain, have a proper email address that goes with it too. A Hotmail or GMail address may be what you had since school, but it looks cheap, in my opinion. When you buy a nice domain, set up the email so you have something like firstname.lastname@example.org or if you choose a business name, email@example.com
Know your services
Don’t fall into the trap of saying you can do this, that and everything in-between. You’ll look far more professional if you specialise, and you won’t get requests for things you’re not confident doing well. Going with this, only put work you want to do again in your portfolio. If you put a project in there that was a pain in the ass, leave it out.
Long days & long nights
I learnt this one the hard way, transitioning from full-time agency life to freelance life. I was working 20 hours a day for 3 months. It actually made me ill, short-tempered and unbearable to live with. But I needed to do that to ensure I got off to a good start when I left my agency job. Those long days sometimes continue in the freelance life, but only when something bad happens or a client randomly needs something done quickly.
If you plan your time well and account for your way of working (like I can;t do 8 hours straight, so I do 4 in the morning, 4 in the evening) you should be fine with time, other than those special days.
Sometimes you need to turn into an agency for a week or so. If you take on a good portion of the work that comes your way, you’ll likely end up with too much for you to do alone. This is where having a small network of people you trust and know do better work than you do help out. I outsource about 1/4 of my work at the moment and it’s a joy, but be careful who you work with. They have your reputation in your hands.
I’m pretty shit at this, but it’s the golden question.
Because I got this, I got a bit of a boost in reputation & notoriety. Most of my work still stems back to getting that. But it does suggest that a reputation is a massively powerful way to get work. Go for awards, competitions, talk on Twitter, contribute and challenge the conversation with mindful well thought out comments, go to meet ups. Just get out there. No one will discover you in your bedroom talking on forums with a silly name.