Things to take when you travel lightly.

I always pack light when I travel - just a carry on and a small backpack.

Here is the list I take:
1.  Enough underwear for 5 or 6 days.
2.  Depending on where I am going 1 or 2 pair of long pants (Northern Europe can be cold sometimes even in the summer).
3.  2 or 3 pairs of shorts.
4.  4 shirts.
5.  1 light weight rain jacket - For cold nights and for rainy days.  I usually wear this on the plane and stuff the pockets full of things I need.
6.  Travel size laundry soap for washing my clothes in the sink.
7.  Portable clothes line - From REI.  I usually rig it up in the bathroom.  Make sure your clothes are light weight and can dry overnight.  (Do wash in the morning so it will be dry by the next morning.)  If you are really lucky your hotel will have a towel warmer and that will dry clothes in 1/2 the time.

I like this one because it can suction cup to the shower wall or you can tie it up too.

8.  Travel adapter and converter - Most electronics like phones and ipads have a wattage that can go in any country, but check the small print on the equipment to make sure.
9.  ATM card - I can usually get cash out of ATMs at the airport - beware though.  Some things look like ATMs but they are money exchange machines and will charge you much more than a normal ATM.  Look for the word that looks like bank.  Avoid anything that says exchange.  In Europe so many things take cash, you'll want to get a couple of hundred dollars at a time because it avoids ATM bank charges and hassles.  My credit union actually allows me to pre-order Euros (or other currency, but it takes a week to come in.  Not all banks do this.
10.  I take travel size shampoo and soap because you never know if your hotel is going to have it.
11.  Travel size fan - you never know if you will have air conditioning or not.

This one is great because it folds and it runs on battery or can be plugged in.
It's also surprisingly strong.

12.  A small travel bag - like a purse - that has a strap that goes across my body.  It also turns into a fanny pack if I want to use it like that - but I don't.
13.  A foldable bag that can become a bigger bag if I need to have additional luggage later.
14.  1 pair of sandals and 1 pair of tennis shoes.  2 or 3 pairs of socks.  I usually use tennis shoes when doing a lot of sight seeing because it requires walking a lot.  My sandals can be worn with dresses and skirts too, but they are comfortable.
15.  A book to read on the airplane.
16.  Earbuds with a microphone to watch movies on the plane and to make calls from computers (Google Voice, Skype)
17.  I always set up Google Voice right before I leave so the calls and texts go to my e-mail and I don't have to spend the money when I answer my phone.  When you have Google Voice on your computer, it will let you make free phone calls to anyone in the USA.  It does cost money - I think 10 cents a minute - to call anyone not in the USA.  I created a video to help my Mom set up her Google Voice.  Here it is: