So! Here's my guide I said I was going to make.. well, if you're on a discord yeah..
Get an idea for a pallet and ability. Don't make the color too neon, as it hurts eyes and it sets a bad concept. It can be a light blue, a dark purple, even one of the pallets like Keebys, or just keep it pink if wanted, but you must follow...
ADD UNIQUE DESIGNS. I swear, this is what ruins a lot of characters. THEY'RE JUST RECOLORS. Add somethimg, anything, like a new hat, or shoes, maybe facial markings. Heck, even a mask or a cape on a character is more interesting! Just don't keep it as a recolor. I stress this to you, it puts a lazy feel to your character. Okay, I'm sorry for that mini rant... onward!
Don't get too complicated for your unique design. Don't add tons of miniature details onto the character, just add something simple, like shoes and a hat or something. Next step...
You might be having difficulty. Think of their personality and other steps first then. Maybe they're a kind gentlemen? Maybe add a bowtie. Consider the possibilities.
Here's a guide on GOOD CHARACTER DESIGN