Prior to preparing a bottle of formula, wash your hands first.  Then, follow the instructions on the formula label precisely (source).  Add the correct amount of powder to a bottle, then mix in the recommended amount of water.  Place the cap back onto the bottle, and shake it well.   Per the package instructions for Enfamil Enspire, use one scoop of unpacked, level powder for every two ounces of water. If you want to heat the bottle of prepared formula, do not use a microwave because it can cause hot spots. It is important not change the ratio of water to powder without speaking to your pediatrician.  Doing so can reduce the amount of calories and nutrients your baby consumes.