Everyone (or 90%?) of people have this problem at the beginning. I asked for help too, but this is something that you'll need to know by yourself. The time of trying (morning, middle day or night) depends of each person. Your ability to meditate (very important), and modification! You can use herbs, or sounds, or whatever do you feel better.
I can only to do this at night (but don't try this tired because you're going to waste your time), so sometimes I drink some tea (mixed, and I don't really recommend this way) and I use binaural beats like this one (very useful and really works more faster than other, but can be different for you):
Remember, no one is equal and what is easy for me could not be for you, so you need to try and try again, until you find the best way ...remember that in this forum there is many topics about this, so check it later...