Here is the short list run down from my experiences. In no specific order.
1) if you force carbonated, then it is probably overcarbonated. This will lead to extensive foaming, EVERYTIME. Turn the CO2 to the proper pressure for your beer and agitate the keg, then release pressure. Do this a couple of times a day for a couple of days until your keg stabilizes.
2) balance your lines. There is lots of reading on this. If your fridge temp is approximately 40 - 43 deg and you use 6' of 3/16" beer line, you should be allright. This will give you a pressure setting of approximately 10 psi which will result in a carbonation of approximately 2.2 volumes. For more specifics, please read lots because there is lots of other variables.
3) your fridge tempertature needs to be stable!
4) if you are using a tower, the tower needs to be cool! (or the beer in the line on the way to the tap will warm and cause foam)
5) a warm tap will result in about an inch of foam or more on the first pour, (just until the beer cools the tap, you will see condensation)
6) you need to pour the beer correctly / open the taps completely and angle the glass correctly (dont worry, lots of trial and error will perfect this
Have fun getting it right,