have (something) on the brain
to be obsessed with something
My sister has tennis on the brain and she is always talking about it.
Easy ways to Make Money Quickly
Perhaps you enjoy writing, managing Facebook pages or doing a little bit of graphic design in your spare time. There are so many freelance jobs out there that require simple skills or just time that someone else might not have.
And the best thing about freelancing is that you can work for clients in the UK and around the world with just an internet connection from home, to your own hours whilst developing valuable skills.
A great place to start is with the leading freelance site Upwork.com. Or try using our student job search to find freelance jobs closer to home.