I have shoulder length hair and when I need to put it up, I usually do a bun. I gather my hair in a ponytail, then holding the hair against my head, I wrap the ponytail around into a bun, then secure it by using an elastic hair band and wrapping it around two or three times. I don’t know if my explanation makes sense, but it’s easy to do. I mainly do it since it’s simple but I’ve been told that it’s a good look for me. It’s not super tight, so sometimes I might need to take the elastic band off and redo it, but that just takes a minute.
But also I’m an engineer and looking polished isn’t high on the requirements so I often just wear my hair down.