You must have absolute concentration. Long prayers never let you concentrate, nor can you be completely sincere in them. When you read prayers from a without absolute devotion, concentration and sincerity, it is just like reading a book.
Try to pray everyday in the same place, as you will build strong and pure vibrations in that place. Of course, it is OK to pray in any place, but if you choose just one place the good vibrations will reflect back to you and this will help you greatly.
You must have faith. Even if you pick up a stone from a road, wash it, keep on a table, and worship it sincerely, your praters create good vibrations and those vibrations will be absorbed by the stone. Your sincere daily prayers create good vibrations around that stone and place, and this vibrates back to you, bringing you peace of mind and wisdom, and even purifying your soul. Just have complete faith in God and be absolutely sincere, and your prayers will work wonders.