I usually take a real life animal and do something major to it, for example with my Lurrikai and jellyfish - I turned it into a bubble-covered humanoid based loosely on a jellyfish. Perhaps that might help?
Also, a general idea for the world might be a good idea first. For example, Ichidus is a mainly sandy part of Renadia, so I thought “what animals typically inhabit deserts?” The first thing I thought of was a mouse (for some reason), so a mouse became some of the basis for my personal species Ichidenne.
I just don’t want to give you any ideas you might not like, it’s largely something you should do so that it’s more likely to stick with you for longer.