TREAD TAJIKISTAN
Dress
Tajiks are often quite well turned-out. In pressed shirt and tie with polished shoes, their university students have a level of class you might only see in the UK at Oxbridge exams time. Attention to dress style is quite important, though as is so often the case, men have a little more freedom than women, although in the city everyone has a little more freedom.
It is important to remember that for everyone, you are generally expected to remove your shoes when entering a house or sitting on a tapchan - this is a raised platform around 2m x 2m, usually found in gardens, for relaxing and sometimes eating. Though most will be understanding that you might just be an ignorant westerner, avoid showing the soles of your feet or shoes to anyone, as this can be considered a grave insult.
Men
Once you're a grown adult, it is generally the case that you will wear a collared shirt and not wear shorts. For Tajiks, shorts are only worn by children. The people of Dushanbe are in general very open-minded, and they can accept that westerners might want to wear shorts without seeing it as a questioning of their values. Bear in mind, however, that just as with any city in any part of the word, wandering around dressed in an unusual manner at night time can induce harassment that might not happen during the day.
Contrarty to some advice I have seen around, Tajiks are entirely open to the idea that wearing shorts when running is far better than wearing long trousers. Though it might be considered indiscreet if you wear the extremely short ones that amount to little more than underpants with flaps of fabric attached at the front and back, just as it often is in the west.