Beginner

Here is a little tutorial on how to make a dress for your female characters.  In the Cloth setting there is a sewing setting that makes this technique possible.
He shows how to make some simple design of the dress, assign some of the dress different materials, and how to fix certain issues of the simulation.  The straps start to fall of the Character and he makes a bridge on the back of the dress.   But in the tutorial below, using weight maps and the Pinning section would of solved that problem, and of course gives you more control on how the dress reacts.

Pixxo 3d, I like his tutorial which goes over basically the same thing as the dress for the women but has pants.  The important thing that makes making clothing this way is to get your outline, and then extrude, and then delete the faces for the openings.  He deletes the faces for the top of the shirt and the bottom parts for each leg, and the arm pit areas.  The other videos talk about using a solidify modifier and it's important to remember which modifier is above or below the other.  The intermediate tutorials go over that.

 

Intermediate

This Tutorial by Anèésh Arts really helped me understand cloth simulations His use of multiple examples side by side really are wonderful.  He starts his video with a simple cloth simulation, then One on a Character, and then Multiple clothing objects on a character.  (He bakes a simulation for each one, turning off each clothing object in the collections manager) He goes over initial settings, and what to do when you run into issues.  The important part is the weight map, and the use of the blur tool for "Pinning".   His bonus tip at the end is awesome, be sure to watch that.  He goes over how to add wrinkles to a character simulation that doesn't use a "outfit" object.  

 

This cloth sculpting tutorial shows how to use the mask tool in sculpt mode to make the shape of the clothing, and then using the various tools to sculpt the folds and creases.

 

Advanced

Cg Cookie has some great tips on handling cloth.   He uses constraints.  From what I've seen his method gets pretty good results.