Here are the steps I go through for deciding on a cosplay, great for beginners:
Step 1: Is there a character you would cosplay as no matter what? (if yes: step 5, if no: step 2)
Step 2: What is your budget, experience level, and interest? Interest can be genre (eg comics), theme (eg DC), or anything else (eg obscure, funny, teams for group cosplay etc.)
Step 3: How much does accuracy matter to you? To some people it’s fine to put throw on a Batman t-shirt, other people want a Kevlar cape. Does it matter to you what you look like vs what character looks like? (Also, never let anyone decide any of this step for you. You decide how much accuracy matters. Well… within the confines of the law. I’ve worked cons. Your cosplay needs pants and no, you may not bring an ak-47 with ammunition in here, there are children here, do you really think that is appropriate? ).
Step 4: Browse through character guides of things that interest you, watch your favorite episodes, read your favorite issues, etc and look for characters you think you can do generally baring in mind steps 2 and 3.
Step 5: Make a list from head to toe of everything you need and make a separate list for everything you want for the costume. Decide if you can buy or make all that. (if you can’t go back to step 1 or 4)
Step 6: Consider time if it matters (going to a specific event). Given a decade and enough paint, glue, and cardboard I can make a costume for just about anyone that looks amazing but I don’t have a decade. Whatever time you get, double it to be safe.
I make at least one cosplay every year for my local con. It has gotten to the point that I can run through this whole process in my head every time I see a character I like even a little. You should have fun with it, accuracy isn’t always the best course. Sometimes you shouldn’t think, ‘how can I look like [character]?’ sometimes the best cosplays come from ‘how can I make [character] look like me?’
Good idea. Might go with a Rebels or Armorer disign for the pack to save space… That could work!