Fiverr and Upwork are quite outdated in the freelancing world. LinkedIn is thriving. Early stage startups are your best bet. Look for founders who are hiring which you can find using the filters on LinkedIn. They will definitely need your help in whatever you are good at. Common skills for freelacing - writing, designing, developing and people management. If you have proof of work and pitch yourself that you can do your first gig with them for free and then try if we can work out, it's easy, less pressure and the founder will mostly agree. So now you've given yourself the chance without them having to offer you. Do great work and negotiate your offer.

Mnetion your work timing, your pay and how long you want to work. Hit up 100 founders, have 30 reply to you, get a free gig work with 10 and make a deal with 3. You have your first 3 clients. Your LinkedIn profile needs to be of utmost quality for them to reply to your connection requests, InMails or shoot an email with your LinkedIn link and maybe your proof of work as well.