I'm currently experimenting with a wide variety of sites - GPT, PTC, Survey, Game, etc - just to see which are legit, and how much one can make, and how much effort would it take.
I've found, in general, most sites are basically similar with offering a combination of some pay to click, surveys, tasks, shopping, coupons, offers, videos, and more. What it basically comes down to is what things being offered at the site work for you. If you are in a good demographic - sign up for sites with surveys. If you like busy work - try the tasks. You like trying out new products - look for sites that provide offers to your liking. Like shopping - check out sites that offer coupons/shopping. Like playing games - try those out.
Other thing that seems to be common is whatever the site offers typically tends to go in feast/famine rounds. Some times there are more things for you to do than you can handle, other times you struggle to find anything. Just take the days with not much as a "vacation" or "day off" from you online work and go see a movie or do some reading - so you can be rested when the next feast arrives.
How many you do is up to you and how much time you want to spend. I've found for me, there are some sites I can make some pretty consistent money, and others are slower earners - so during "feast" times, I take priority with my good earner sites, then then move to the others if I still have time/motivation.
General rule - it all adds up. If someone told you if you went outside, that you would at least find a penny each day - but could pick up 50 cents, a dollar, 5 or 10 dollars - all you had to do was go outside each day to look for it on your property - why wouldn't you? That's just like all these sites.
If you are curious - sign up for the free ones you find, then try them out for a few months. Over time, you'll find what you like and what you don't like - and which work better for you than others. Take comments from people who say it takes "too long" to make money on a site with a grain of salt - how fast you make money shouldn't be the important thing. If the site pays, who cares how long it takes to make it, as long as based on the rules, you'll eventually get paid.
One thing I can say - from all the sites I've signed up for, FusionCash seems to be the best site that guarantees you a payout within about 5 months. As long as you do the daily email and daily pay-to-click task - you can't miss. Anything else you do (forum, surveys, tasks, offers, videos, etc...) - just speed up your cashout. I've only found two other pay-to-click only site that's as consistent in guaranteeing a consistent payout with minimum effort.
Hope you find this information useful and inspiring - and good luck on your own adventure!