I would second, third etc many of the suggestions people have already given. A few specific things I've found when backpacking (including as an early 20s female travelling by myself):
- as someone has already mentioned, ziploc bags are a must. I tend to use them for dirty clothes - both to keep them separate from the clean stuff and so when you go to do washing you can just pull the bags out and get on with it. Also useful for keeping things like power adaptors safe and dry and easy to find
- look at not only the ratings, but recent reviews on the hostel booking websites so you have a bit of an idea of the specifics of good and bad aspects of places. You'll soon learn what you're willing/able to put up with, and what you're not
- hostels with washing machines will be a godsend
- be prepared for travel plans to go awry, have at least a vague idea of backup options (particularly when you're connecting to another bus/train in a midway town) and be able to entertain yourself while you wait. A sense of humour is even more important when travelling on the cheap!
- avoid any 'YHA' branded hostel at all costs. In my experience, they're uniformly terrible
- I've found that I've been able to get away with booking only a day or two ahead in most places during autumn and winter. Not been to Europe in summer, though, and imagine that approach would not work so well
- your camera's memory card is pretty much the most important thing you'll take with you. Given how long you'll be away, it's probably worth having some kind of way of backing up your photos as you go
- don't be careless with your belongings in a hostel, even if you're just ducking out of your room to go to the bathroom. I've seen people have stuff they've left out or easily accessible stolen while away for only a matter of minutes. That said, so long as you're generally sensible about your belongings, you should be fine.
- definitely head to Eastern Europe - my favourite part of Europe, and changing so quickly that it will be unrecognisable only a matter of years after going (necessitating you go back again to see how things have changed, of course!
![Big Grin :D :D](https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f600.png)
) Budapest, Estonia and Transylvania are highly recommended