--I'll have already put months of training on my horse to do the maneavars correctly. I don't show at the national level, so I don't need a world class performance horse, but I do want to do things correctly.
--The week before the show, I will clip and trim fetlocks, bridal path (I keep a very small one, just enough to let the halter/bridle through), and trim up any mane or tail stragglers if I need to. I show locally, so I let my horses keep their manes and tails long for flies. I don't pull. I also don't trim away all the hair in the ears (I let them keep it for flies) but I do make them look neater. I do all this the week before, so the trim lines have time to be less noticeable.
--A day or two before the show, I will give my horse a bath if they need it. I will also wash any support boots I need for gaming, if those are dirty. I will also make sure my show clothes are pressed, cleaned, and ready to go, and make sure my hats are cleaned and shaped.
--The day before the show, I will trim whiskers around the eyes and the muzzle, and the throatlatch area. I also groom the horse up nice, so it's not as much work the next day. If my tack is really dirty, I'll at least dust it off. If I've got time the day or two before, I will oil everything up nice. I don't have a separate show and "working" saddle.
--The morning of the show, I will wash any white stocks or stockings the horse may have. (I do not apply chalk or white paint because I put sport boots on for the gaming at the end of the day, and I don't want that getting in my boots.) I will put on hoof polish. I will brush them up really nice with Show Sheen on the coat, and Cowboy Magic on the mane and tail. I'll also apply fly spray, as I want them to be comfortable the whole day.
--When traveling, my horses always get their legs wrapped in the trailer for protection, and some support.
So my grooming routine before a show isn't a whole lot since I don't show at a high level, but I do like my horse to look neat and clean, and I want myself to look neat and clean too.
Just because you only show local, doesn't mean you can't still present yourself nice.