Welcome
This thread is for those who want to learn to sew and hand make their own costumes. This topic isn't an easy topic, because I can't be there in person to teach you, but I'll try to tackle it.
In all honestly it isn't hard to do it by hand or machine. Doing it by hand can be longer, but if you're not comfortable with being able to make a seam by machine or if your going more historically accurate you need to know how to hand sew. That being said you also need to learn how to do it by machine. Machine sewing can make things quicker and can help it look professional.
While I can't be there in person. I have collected videos on the subject done by some fairly well known and famous cosplayers to help you. If one person doesn't help you, or does it a way for you to understand, please watch a different cosplayer. I recommend watching them all as you may learn a lot about sewing that way. I also added a list of recommended books for your collection.
I hope this guide will help those who want to amp up their sewing and cosplay game. Please feel free to provide any questions, comments, or feedback to help me make this thread better.