You may be new to cosplay. Heck, you may have been cosplaying for 10+ years now. I'm going to share my observations with you on what makes an awesome cosplayer. Using my tips you too will be awesome. Are you ready? Brace yourselves. Steps are coming.
1) Be passionate about your character
So you're male but you just LOVE a female character? GO FOR IT. You're tall but your favorite character is short? WHO CARES. I could go on an on making these comparisons, but it's really unnecessary. The point is, if you love a character as long as you're passionate about portraying that character you will look amazing.
2) Celebrate cosplay of all skill levels
Cosplay is about having fun. This dude looks amazing. Did he spend a million dollars to be the evil queen? Certainly not, do I know who he is from a distance? I certainly do! Don't be afraid because you can't sew, or foam-smith. Most cosplayers understand that others are on a budget. If someone is a jerk to you over your skill level they're the one with the problem.
3) Don't make fun of people that buy their costumes.
Some folks have 0 sewing skills, and guess what? They don't want to learn how to sew. Is that a problem? No. It leads back to the whole cosplaying is about having fun. I'll be honest, 90% of my costumes are made by hand, but sometimes I just don't have time to make multiple costumes for conventions so I'll buy one if it looks a way that makes me happy. So, you find a costume you like for sale and you can afford it? Snatch that up!
4) Be open to new Techniques
Sometimes your way of doing things will help another person out. Sometimes it's the other way around. Keep an open mind and talk with other cosplayers and costumers. I know I love asking others how they made different things and learning new things. Keep an open mind because cosplay really is a community.