Ask HN: Where can I find remote or quality oriented freelancing work?

I'm currently working 40h/week as a backend php developer and I think I can put an extra 20 hours every week to increase my earnings. However, I struggle finding remote work or above the average freelancing projects. Basically I don't want to waste my time on sites like freelancer.com where I have to compete against many low-quality programmers who place low bids just to win projects and then they mess them up.

Where could I find jobs like these?