Just had a look at your problem . Assuming it is an open D on the e,b and g strings . Try fretting the d on the second string first , then with the first and second fingers touching at the last knuckle hammer on the g and e strings , this way they should hit the strings at the same time . Keep your finger close to the fretboard , the shorter the distance you have to move the more accurate you will be . Doesn't matter if you touch the b string , it's already fretted further down . An alternative if you are having a co-ordination problem , fret the d on the second string and use your index finger to to barre across the e, b and g strings . Hope it helps . Practice .