Responding 2NT to a 1 of a Suit Opening has traditionally been played as a balanced hand with 10-12 points.  This is has long been felt to be a poor use of the bid and Jacoby has become the preferred use of it.  Using the Jacoby 2NT response shows good support for partner and a sound raise to the 3-level or better.  Some players prefer to use it as a sound raise to the 4-level or better.  If you feel this is too advanced a method for you then it is still recommended not to use the traditional method.  If you have 10-12 points and a balanced hand it is better to offer a new suit initially and to rebid 2NT (so long as an 8-card major fit has not been identified in the meantime).