how long do you do it and any good tips on this?

http://www.wikihow.com/Hard-Boil-an-Egg

Be careful to avoid overcooking them and to avoid using hard-boiling water. You know they're overcooked when they are way too hard or they develop a green (cupper) layer. They would still be healthy, but they wouldn't be as tasty.

here's what i do
put the eggs in a single layer in an appropriate sized pot for the amount you're boiling
add enough water to cover the eggs plus about an inch or so
bring the water just to a boil
remove from heat, cover and let them steam for 15 minutes or so
take them out of the hot water and put into an ice bath (ice cubes+cold water) to stop the cooking

pretty simple

this.

you can also just kill the heat on the stove if you're using electric. will cook them slightly faster

This works perfectly.. but i usually leave them in for only 10-12 minutes!