Do chest compressions at a rate of about 100 per minute. This means you are doing just under 2 compressions every second. It should take you about 18 to 20 seconds to do 30 compressions.
Allow the chest of your victim to recoil fully between compressions.
Practice on a CPR dummy, a doll or a stuffed animal by doing 8 chest compressions every 5 seconds. Time yourself to ensure you're doing it correctly.
Compress 1 to 2 inches with adults. For infants or young children, compress 1/2 to a 1/3 the depth of the chest. You are trying to trap the heart between the sternum and spine and it will take deep compressions to do this.
Count aloud so you don't do too few chest compressions. When counting, do not put an "and" between counts. If you lose count, err on side of thinking you didn't do enough. Do a few more chest compressions before giving breaths.