[JCF]

Drink only bottled water - and be sure the top is sealed.
Brush teeth with bottled water.
No ice cubes unless you know the ice is not made with tap water.
Cutting fruit can introduce bacteria from the outside so wash before you slice.
Eat in only better restaurants - though the best food is often found in smaller less sterile places.
Squeeze lime on salads (acid will kill any bacteria that might be there)
Some say daily doses of pepto bismol will keep you safe - not true.
Wash your hands often.

You have to accept the fact that it you might well get sick, no matter how careful you are.
Some depends on your bodies ability to fight off the bad stuff.
Be careful but I considered the misery of the 24 hours I was ill a fair trade for the wonders of that place.

Be careful but don't let the fear of trying a taco from a popular taco stand cause you to pass up something your nose leads you to.

Wish I was there.