Your suitcase should be lightweight and travel friendly. These days Samsonite and all other good brands have multiple travel pouches inside of their trolley bags and a 360 degree rotation wheel for easy maneuverability. North face also has some durable bag packs and Luggage bags in Nepal.
At the airport you always see people carrying gigantic travel bags with them. No one knows what they stuff in there because unless you are planning on living on the mountains you will not need that much stuff. When travelling you should always keep clothes that can be worn a couple of times over and over again and toiletries that are absolutely necessary. So there is no need for body scrubs and face masks. Basic toiletries include toothbrush, tooth paste, body wash or soap, deodorant, face wash and shampoo. Anything above this is only going to unnecessarily add to the weight of your luggage. There is no country in the world where you will not be able to find these toiletries as well. You can always replenish this stuff from the tour country.
Are you planning a business or leisure trip to another country for a week? Here is what you will need; two pairs of socks, 3-4 underwear/boxers, a pair of slim shorts which also double as sleeping shorts, cargo shorts if it is summer, 3-4 casual tee shirts and a fleece jacket (depending on where you are going). If you are planning to attend some formal affairs then keep a formal pant otherwise your regular jeans and wind pants will do. As far as footwear goes you need a nice light pair of flip-flops and sneakers are an absolute essential for long walks around the city, rather than keeping formal shoes it always better to keep driving mocks. Again this depends on whether it is a business trip or a vacation. In the accessories department you must not forget your sunglasses. Now this is one thing that may not be easily available at your travel destination. Sunglasses are also an item you are comfortable wearing so it might be that sunglasses available there won't be the same. For the flight you can keep a good book, headphones, an ipad to watch movies and a neck pillow.
When it comes to electronics you should always keep all the travel accessories you might need. Bring all your chargers for phone, ipad, ipod and camera. Camera is also essential if you are going to a new place, the phone cameras are usually not enough. Nowadays people carry bulky DSLR cameras for professional photography. An external hard drive will store all the important files safely till you reach back home. Rather than keeping your expensive iPhone, we advise you to keep ha smaller lighter junkie cell phone, so that even if you lose it there it won't be a big deal. All countries have different electricity sockets so keep a universal adapter with you.