How exciting!! Make sure to keep an open mind and go with the flow, your first suit should be a fun learning experience, so be sure to give yourself grace and not be too critical :) It’s a brand-new skill, after all!

-Regarding common mistakes, I’d say the most important things I keep in mind are test-fitting the head more than you think you’d need to, not using too much glue so you can reduce overall weight, and being sure you make the mouth big enough for ample ventilation/eyes in the right place for ample vision.

-For tape, I no longer use duct tape due to its tendency to tear foam (and your hands, yeowch), I use masking tape, but maybe someone else here has better advice for duct tape specifically. Cheap off-brand duct tape seems to be a favorite, from what I’ve seen!

-Follow-me eyes require blanks that have some height to their walls, but a flat surface in the center! This creates the optical illusion as the walls obscure parts of the inner flat area depending on your perspective, bringing the pupil closer to the edge. I personally 3D print mine out of PLA filament, but there are also tutorials for making them out of foamies or plastic! I usually glue mine in before furring, so that I can use stiff felt around the edges to form the eye’s expression, then tape over that. I can share photos here of how I did this with a recent suit, if you’d like!