actually guatemala ciudad is an ugly and dangerous city for tourists. you shouldn’t walk around there on your own if you don’t know the city very well.
apart from the ugly zones where mostly poor people live and where the crime rate is high, there are a few nice places to go.
e.g. the main park in the zone 1 which is surrounded by the national palace and a big church or a few streets afar the national post office building.
the “mercado central” – central market is a good place to get (tourist) stuff, fruits or food – even though a lot of europeans wouldn’t eat what they sell in the small, not hygienic “comedors”...
moreover you hear from a lot of people, that you shouldn’t eat cut fruits from the streets, so it’s better to buy them as a whole.
i can absolutely recommend the piñas and the mangos, i just loved them!
good hotels, restaurants and places to go out you can find in zone 10, called “zona viva” or in “cuatro grados norte” in zona 4.
finally i would recommend other parts of this beautiful country frist (e.g. antigua, monterrico, semuc champey, rio dulce, tikal…)
nevertheless i would never like to miss the time i had there!