It is important for females (in particular) to wear appropriate clothing in many places, particularly if travelling to the country areas. The more respect that women show, the more respect that they will receive.
Showing too much skin is a sign of promiscuity to the Muslim people and will result in a lack of respect and even hassling. Therefore it is important for females to cover their elbows and knees if they do not want unwanted attention.
The touristy areas are more liberal and you can get away with less modest clothing. However you will be given more respect and receive less attention if you wear more discrete clothing and cover more of your skin.