1. Sign up at prolific.ac
2. Setup your profile takes around 5 minutes.
3. Wait for the first survey, it usually (80% of the time) is worth 5£ and takes around 25 minutes.
4. Do the survey as quickly as possible (but without rushing too much) and cashout.
5. Delete the account and restart (Why? the First survey is often high paying for inviting you to spend more time there)

TIP: You can make a bot for signup and complete info automatically, which will save you a lot of time.