The best way is simply not working full-time. Work part-time. I know you'll now come up with all sorts of excuses why it's hard/impossible. But hey, you want to do a creative project. That implies you are a creative person. So get creative. I assume the partial loss of income is not a problem. Can't be in our industry. So go negotiate with your boss. Negotiate hard. Your boss can't agree because he needs someone to occupy a desk - work half a day. Trade other benefits. Get your colleagues on board. No luck - change jobs, become a freelancer. Hack, you could even become a freelancer at your own former employer. There are plenty of options. Get creative!