The "Glass Work" I've done, (not a lot but have re-bottomed a 17.5' Boat).
You need to use more resin first, then lay out matting or cloth, then lots more resin, then mat/cloth, ect, ect.
Worked best as a "Team effort", I guy mixing, one cutting, (cut's can be done in advance) and one guy spreading, don't be afraid to throw away "Chip-Brushes" they are cheap for a reason.
A handy little spiked wheel roller on a handle, (name just out of reach by my coming B-day, Damm, Youth sure is wasted on the young), Sharp points help with rolling the glass down. The fiber-glass roller looks a lot like a seamstress type thing, just much larger and many wheels not just one.
I learned to mix a bit slow, (Hardner to resin ratio){LESS} in summer or large projects. Small and or cold can be mixed a bit "Hotter", {MORE}.
But like most things like this, There are artists and Good enough!
PS: learned the hard way that to patch a boat, minimum of 4-6 layers glass, 8+ better!
Build up beyond whats needed and grind back after cure!