I think you're alright as far as docs are concerned - if you have any prescriptions (including for glasses) you might want to take copies along in case you need to renew while you're traveling...otherwise, money, passport and whatever visas, tickets you should be good to go.
Usually hostels have some sort of lockers, it's a good idea to use them if they're provided. Often you'll need your own lock - combination locks work well if you can remember the numbers, keys are prone to loss.
I've never brought my own bowls/cutlery (except a Swiss Army knife), but some people do - wait to get more opinions on this one!
Not a bad idea to have a back up card in case your main one goes missing, though it's good to keep it as an emergency back-up only, so you don't risk your budget! Keep it separate from the one you use daily, in case you lose your wallet or something. Also, keep a record of the number to call if you need to cancel your card - some people send this info to themselves as an email so they don't have to drag lots of paper around. Or leave the number (and your card number) with a trusted family member so they can call for you if you have a problem.
There was a big debate about the utility of daypacks - I think it's in the Gear Forum. A big messenger type bag would probably suffice for anything you'd need to carry for just a day around town - having a full up daypack is generally more than you need for a day, and sets you out as a tourist. Here's when being a girl is an advantage, no one looks funny at a girl carrying a big purse!
If you're just going to be walking around town for a day, you'll need something to carry a camera, bottle of water, maybe a guide book or notebook, and possibly a jacket...doesn't have to be that big. If you intend to do short overnight trips or do actual hiking day trips where you need to bring food or overnight gear, then it would be worthwhile to have a proper daypack, just depends on what you plan to do. When we lived in Lithuania, a lot of men I knew who were traveling in the region, found the best solution was to buy some water and snacks, and throw their other gear in the shopping bag (you have to buy that too, there). Almost all the locals walk around with a bag, so you blend in more, and if it's a bit crumpled looking, nobody thinks there's anything valuable inside. But look for that debate, you'll get lots of info.