>>8674481There's a closet cosplay thread and a fashionable manga/anime thread, you could look at those.
Otherwise, I'd say any characters that have normal clothes. Spike from Cowboy Bebop, Ash from Pokemon, Desmond from AC can all be done with the help of any normalfag shop. Seifuku is a great idea, as is any sort of vaguely recognisable uniform. People might not know what you are but they'll know what you're going for (eg the might not know you're waitress Mikuru but they will know you are a waitress).
Pokemon gijinka tend to be pretty easy too, especially if you go for the more well-known ones. If you want something immaculate go for something else, but they're good as a last resort costume (cut out a tail, paint it, wear clothes in that colour scheme. You might very well look like shit, but you won't look shittier than everyone else.)
Things like Free!, Yowapeda, Kuro no Basket, some of the outfits from Gekkan Shoujo Nozaki Kun and pretty much any casual outfit from Sailor Moon can be bought and/or assembled in about twenty minutes flat.