Types of Canvases and Paints
Choose the right canvas for the type of paint you are going to be using, as most canvases are designed for specific types of paints. For example, there are watercolor canvases, which are generally paper-based, that are designed for watercolor paint only. The most common canvas, called cotton duck, is best suited for oil paints while linen canvas is geared for acrylic and pastel paints. Oil paints are a good choice for beginning painters because they dry slowly and can be reactivated with turpentine or other liquids. Acrylic and pastel paints dry quickly and allow the artist to complete their projects faster. Canvases are available in different sizes, as well as raw or finished form.
Choosing the Right Brush
Selecting a brush is just as important as picking out a medium or paint type. There are a number of different styles of brushes and it will eventually become a matter of personal choice once you decide what brushes to use. The bristles are made from a number of different items, from synthetics to animals (such as sable or hog bristle). Choosing a brush set is a good place to start, as it will give you an array of brushes to choose from and will have various sizes which can come in handy when painting large scenes or fine detail work.
Subject Matter
After deciding your medium, determining your subject matter is your next most important decision. Many artists are as defined by what they paint as well as how well they paint. For beginning artists, small still lifes are usually a safe choice. They are easily manipulated, can be easily lit and, depending on the subject matter, are easy to complete. As you become more advanced, you may want to move up to more difficult subjects, such as nature scenes or live models. For abstract art, it's not really a case of starting small but more of starting with fewer colors and shapes before moving on to more complex structures and ideas.
Light Source
When painting on canvas, it's a good idea to keep in mind where your light source is for your subject. Whether you are painting a still life, live model or even a scene from memory, the lighting should remain consistent. This means incorporating shadows and light in your painting to make it more realistic (unless painting an abstract). If painting inside from an actual source, mark spots on the floor, table or wherever for the model to remain, in case it or she has to be relocated, as well as your light source. If using natural light, try to paint around the same time of day in the same conditions so as to recreate the subject perfectly and consistently.