It is essential that you establish a bedtime routine that works for you and stick with it.  Your body and mind need to have consistency at this time so that you can learn to fall asleep naturally.
Write down your plan of action, including bedtime and waking time.  Keep a list of the herbs and vitamins that you have tried as well as what teas you prefer.

Stick to your routine and after a week or two has passed and you are still experiencing difficulty sleeping make appropriate adjustments.  The key here is to be consistent and determined.

Your goal should be to establish a regular sleep schedule.  Wake up each morning at the same time and try not to oversleep. Sleeping longer in the morning will only make you feel groggy and disoriented. Sleep experts believe that you should get an average of seven to eight hours of sleep each night.  You can’t make up for sleep that you lose during the night by sleeping in later in the morning.

Simply do your best during the day and try to get back to your sleep schedule that night.
Try to get ready for bed at the same time each night.  Once you have established what hours work best for you then try to be consistent.