I'm assuming this is referencing character designs. I've seen a lot of anxiety around the visual aspects of character designs being too similar, but I personally don't worry over it. I keep in mind that nothing is completely original, and making character designs and specifically personal OCs, means doing so with confidence and fully catering to myself in what I want the design/character to be.

I think what helps me make unique designs is: I love to push unique features, especially facial features and silhouettes - accessories, hair, mobility aids and body modifications, shape language, even down to smaller details like scars, tattoos, piercings, which lend themself to fully fleshing out a character visually as well as who they are (like why do they have those features). I also am the type to lean into fantasy biology and have created many species for my headworlds (and by extension fanworlds), which many of my main characters are a part of, so that lends to making designs that are more unique to my tastes and style.

I tend to mull over a character's design in my mind for awhile before committing to the designing process. I like to know at least a good base of what I wanna do for a character, so I visualize and rotate their concept for days if not weeks or months. Usually this is most of the "drafting" work and keeps me from getting stuck when actually drawing them. If I AM looking for visual references to start from or to help with the designing process, I like to compile image boards on Pinterest for my characters to get a feel for them... this especially helps flesh them out after I've designed them.

But, if I have a character design in mind that I'm pulling inspiration from (such as I liked the concept, aesthetic or even specific markings), I do NOT pull up the design to reference. That's the easiest way to prevent "copying" someone else's character design, I think... I do like to pull up the design afterward or when I'm mostly through the designing process to ensure that they don't look too similar. In my opinion, if the designs can be mistaken for each other, then that's close enough to "copying" to be a personal issue.

This is all my creative process for personal OCs. For adopts I often start with a visual inspiration from Unsplash (I fave images to use as insp and in moodboards) or am struck with inspiration otherwise, and mess around with the design until I get something I like enough to consider finished/sellable. Not as interesting a process in my opinion, I don't put as much time and love into designing characters for sale, otherwise I'd wanna keep them all.

Hope this was at all enlightening!