Oil paint is an amazing versatile medium. It can be applied in a thick buttery fashion or thinned down to a watery consistency. This versatility opens the door to a number of different painting techniques.
My personal preference is to begin my oil paintings by first sketching out the composition using acrylic paint or with water-soluble oil paints. The popular approach to oil painting is to thin the paint with turpentine to apply your initial layers. Turpentine is quite toxic and I prefer not to work with it. Acrylic or water-soluble oil paints can be thinned down with plain old water and are more pleasant to work with in my opinion.
You can also begin your oil painting by first drawing out your composition. There are a few drawing mediums that work quite nicely with oil paints. My two favorites are vine charcoal and water-soluble pencils. I prefer vine charcoal because it doesn’t smudge like other charcoals and it can be erased easier. Water-soluble pencils are wonderful because they can be applied like ordinary colored pencils and can also be dampened with a brush allowing you to spread out the color.
If you are the impatient type, you may want to...