The biggest problem I have faced, and I suspect it will be the biggest problem OP will face as well, is finding actors. Maybe you could make cartoons since you can make them on your own, but the issue with that is 1. maybe you just want to make something live action and you have no interest in animation and 2. even though animation is more practical since you can do it on your own, it's really hard to learn how to do well, anyone can shit out a go animate looking thing, but good animation is much harder to do than making live action in my opinion.

It can be a struggle to find actors because even if you have a lot of friends, they might be too busy with school or work and there is no guarantee that any of your friends are going to have any interest in being in your webseries in their free time, they might be more interested in partying or playing video games. But also even if you manage to find some friends that are willing to act in your series, they might not be good at acting, they might be stiff or unfunny.

And obviously if you're making something for no money you can't afford to hire professional actors. So let me ask you, what advice would you give in terms of finding decent actors to agree to act in your webseries?