It’s best to travel light. The lighter your load, the more alert you will be walking down a dark alley in an unfamiliar, new town and the easier it will be to hitch a ride in the back of a truck or motorcycle.
You can find almost anything you need abroad. This cuts down on the weight of carrying extra clothes, toiletries, etc.
The most important things I carry are my passport, journal, and camera. Everything else can bought abroad.
What’s worked well for me in the past is a medium-sized duffle bag and small backpack. It’s not as conspicuous as those large backpacks that are very popular among backpackers. I don’t have to check my luggage at the airport so it reduces the chance of it getting lost in transit and, since my luggage is so light, it’s easy to carry if I want to get out and go sightseeing in the city during a long layover.