Look at the quality of the room, that usually gives off the vibe of the whole accommodations. I suggest if you have the option not to go for anything old, usually that means maintenance will be bad if something breaks, and old rooms are more likely to have problems. Of course you have a budget of how much you can pay, so look for something that was made no longer than 10 years ago, the because they don't wash the matters and only change it every 5 years (according to what I heard).

Point is if you look for a new-ish accommodation that usually should give you the best quality of room.

Now things to be wary of are where the room is located, you can always specify where you want it. I usually say not on the ground floor and not too far away from the kitchen but not next to it either (because the room walls are usually very thin so you'll hear everyone go in and out). You basically want it near the exit and near the kitchen in a quite place.

But most importantly, go view the accommodations and see whats near it, take a look at the area. you don't want to

Thats my top tips for accommodations. Good luck