Adding figures to your paintings is a great way to add interest. The viewer will spend more time looking at a painting when there are people. These figures on the left are done quickly and without much detail. Even without the detail a viewer knows what they are. You will see improvement in your figures if you practice them often. They can be done from life or photos or even from your imagination. The samples done here are people walking. It gives action to your paintings to add figures.

Some of the facts for painting people are: there are about seven heads in the total height of the figure, the top of the legs or waist is half the height of the figure, arms hang to about halfway down the thigh. Observing people is the best way to learn the right proportions.

I always look for the light falling on a figure and I use that to create form. Use shadows and lights next to darks, similiar to the paintings above. Try not to paint stick figures, notice how people stand and walk and the angle created with shoulders and hips.
Another important fact for figures is to scale them to your surroundings. People closer to you are bigger than people in the distance. Be sure that your people are the correct proportion to buildings, doors, cars etc.
Use the biggest brush possible and paint shapes to create your figures and add as little detail as possible. A story can be told when you add figures to your paintings. Practice and have fun with it. Try not to be perfect and your figures will be better.