The only challenge to this chord is making certain you do not strum the Low E and A strings as indicated in the chord chart below. If you happen to hit the A string, its not a big deal. It will still sound like a D chord as the A note is part of this chord.
D Major Chord Notes: D, F# and A
Here is a key that will help you read the chart:
Make certain you are pressing down hard enough on the strings to produce a clean sound. Also, as indicated in the chart above, make sure you are only strumming the first four strings. The fifth and sixth strings are not played.