I have often heard people say that they have a hard time getting their characters to do what they want. There are a lot of people that have different writing techniques, so the advise you might be given on how to correct this situation can be many and varied. Being that I am not a plotter but rather a person that waits on a muse, I can only say that I can never write a character until I really get to know them.
This may be the part where some would say I hear voices in my head or a good example of how writers are slightly left of normal, but when I am developing a character, I make sure to take time to get to know my character. Take Destiny Grey, from my Destiny series, for example. It took me two years to really get to know him. I got to know his habits, that he enjoys his sisters baked goods, the way he had a secret crush on the girl at the next plantation, how honorable of a man he was. I got to see his way with horses, the way he prepared for the day with a prayer.
Destiny would come to me while I was sipping my coffee in the morning and discuss his thoughts of family and loyalty. After I got to know Destiny, the way he looked, the things he like to eat, it took another year to meet his daughter and grandson from the next two books in the series. All I can really say about this process is it cant be rushed. I get to know my characters about as well as you would know your best friend. If you give yourself time to know them, then they will do what they do without a lot of prodding from you.
Another tip I have learned in recent days that has helped me visualize my characters is doing an image search. The above is an image of what I see in my head when I describe the main Character of book two, Rosa Jewel, only obviously I see her in traditional garb for the time period.
Here is an image I use for the main Character of my third book, Strong Eagle. I used the keyword, Native American and African American Cowboy. Be as specific as you are able to be and don't settle for the first image you see. When you see your character, you will know it.
Check out my series, The Destiny Series, at http://www.desertbreezepublishing.com/destiny-by-letisha-stanton/ to get to know my characters for yourself. Destiny's Purpose and Destiny's Hope are also available on Amazon.com.