Guatemala is a dirt cheap place to visit, and it has some great scenery and sights, including Tikal, the largest and most spectacular complex of Maya buildings in Central America (other Maya cities are in Southern Mexico, Belize, El Salvador and Honduras). Tikal was buried for centuries under the jungle, when it was excavated archaeologists uncovered a number of temples which were the largest buildings in the Western Hemisphere until Europeans arrived and started doing their thing. As you walk through the site, there's the added bonus of seeing lots of jungle birds, water birds and jungle animals.
Tikal is fairly isolated, so most people fly from Guatemala city, Cancun, or Belize to the town of Flores, which is on Lago de Peten Itza (Lake Peten Itza), a large shallow lake with clear water. You can then stay in a hotel in Flores, or nearer Tikal at El Remate, which is at the far Eastern end of the lake, or even at Tikal itself. The road between Flores, El Remate and Tikal is the only good road in the area.
The few Guatemalans I had contact with were perfectly friendly, but of course the local small-time tourist guides consider rich gringos fair game for a quick round of price inflation; this is also evident in the pricing of local tourist attractions, with one price for tourists and a lower one for "nacionales". If you earn an above average salary then just grin, bear it, and think of how much good you're doing for the local economy; if you're on a tight budget then take a guess at how much it might cost to run a tour, double it, and start bargaining.
Language was a minor problem while I was in Flores, since most Guatemalans speak virtually no English, unlike people in Belize or Cancun. It's only sensible to pick up a few Spanish phrases such as the numbers 0 to 9, 10, 20, 30 and so on, "gracias", "por favor", "Cuanta cuesta?" ("how much does it cost?"), and the most useful phrase of all, "no entiendo" ("I don't understand"). It's polite to say "buenos [dias]" or "buenas [tardes/noches]" before trying out your language skills. I had the receptionist at my hotel write out on a piece of paper "I'd like to take photographs of birds and insects and butterflies", and I gave this to the local guides who took me for trips around the lake.