GSDIESEL300 introduction

Hey everyone my name is Gavin. I am 19 years old and I love graphic design and I'm very skilled with Adobe Illustrator and want to put my designs on shirts now. However I have limited resources and only have 1 12x18 screen with 110 mesh. This makes it so I have to make a new screen after every few shirts I print a design on. Also I use my vinyl cutter to cut my designs as a cost efficient way to make screens. I have a heat press which I use to cure my prints but I must not let them cure fully sometimes because after the first wash most of the image fades away and leaves just an outline of the design. I want to find out how to make my shirts higher quality with heat transfers and screen printing. If anyone has any helpful tips for my problems above please let me know. Thank you.