Applying isn't the same as getting hired. Treat each platform like a real job application and you'll improve your odds — and the rate you're offered.
Before applying, take stock. What's your highest level of education? Do you have professional experience in a specific field? Are you a strong writer? Coder? Linguist? The answers determine which platforms — and which rates — fit you.
Don't apply to everything at once. Pick the platform where you're strongest and put real effort into the application. You can add more platforms later.
These platforms screen. They're not "sign up and start working."
Be honest with yourself. Applying is not the same as being accepted. If accepted, project work may not be immediately available. Projects come and go based on client demand. Treat this as an opportunity to explore — not a guaranteed income stream. Do not quit your current job based on an application.
Once you're in: sign up for two or three platforms. Work availability on any single platform is unpredictable. Multiple platforms smooths out the gaps.
One click and you're applying.