Image from Freelancer's Fashionblog
1. Never forget your own style
The easiest way to spot a traveler (not only by the backpack) is the generic travel attire, jeans, t shirt, specialized travel company clothing. A good rule of thumb is if you wouldn't dress like that at home why where it while traveling. Wearing clothes that are not your style will make you feel out of sorts immediately. Your style is you and no "I'm backpacking" style of clothing is going to make you feel as good. This is a good article on how to mix your style peaces with easy basics.
2. Expect for the unexpected
Traveling is a stressful outing even though its a holiday. I have seen women with everything from cystitis to blood noses due to stress on the body. Always bring extra sanitary products because stress can effect your cycle and you don't want to get caught out when it comes early. If you are taking an oral contraceptive time zones will affect when you take it up and its effectiveness. If you are prone to any stress related illnesses be prepared. If you do need any womens health services while traveling Woman on Waves has a grate country by country search engine.
3. Go with the flow
I don't mean doing anything illegal or unsafe but with new experiences and emotions. Take the good with the bad. Do things that you wouldn't do with your usual friend group, if you don't normally get to dance get down on the dance floor if it makes you happy. When you are sad and feel like crying, go ahead and cry, it will make you feel better afterwards to let it all out (the shower is a good place I have found to cry that is private where you won't feel embarrassed) .
4. Pack for where your going
Hot climate-light layers, cold climate-warm layers. Don't forget about in door heating and aircon. You will boil if you can't take off your heavy winter clothes when you are inside and will freeze in flimsy summer clothes without a cardigan or scarf to wrap around you in aircon. Take religious and cultural customs into account when dressing. If you are expected to cover up don't go flashing skin, you will invite unwanted attention. If you are unshore about what to wear this artical may help.