The following tips also apply to any other method that sprays the paint, like the so-called airless tools, paint guns or others. First, it may seem easy but if the user doesn't know the approach, perhaps something is going to be badly finished in the trial and error process.
If possible, try to test the device flow rate with water toward a flat surface
This is a safe and clean method to observe how the spray goes.
Applying paint without lineal and even movement usually creates drops and ruins the finish
The objective is to create a flat, even color so first practice the movement for a constant speed and distance toward the surface. This distance varies with the air pressure and flow so if you aren't sure of the tool or paint manufacturer don't provide indications, use an appropriate test surface.
If you fail applying linear movement and a constant paint flow say waiting too much in a zone or adding after, the result could be disastrous as it's practically sure that you will notice how these spots have more bright or a deeper color than the others as the paint layer is uneven.
Try to avoid spraying in angle
It has to be with the amount of paint that the surface receives when there's a right angle with it or not.
A suitable flow is a must
An airbrush like air flow doesn't fit for large areas because they are designed for not providing too much paint. It's necessary to look for specifications of gas liters per minute or similar, and compressor power to guarantee that the painting system operates without wait until the device restores the suitable pressure to apply paint.
Overlap between passes at a 50% with the last
In an even linear motion, the most used overlap is this. So if you imagine that each pass is a two-lane road, the next one should be overlapping a single lane.
Finally, the right paint, viscosity for each work and with no toxicity
Not every tool sprays the densest paint, thus a thinner comes into place. Look also for the recommended surfaces because sometimes there are main incompatibilities or prerequisites for being applied.
For instance several synthetic paints and thinners are very toxic, while different acrylics are safer and less prone to originate a mess. Each paint has different qualities and the toxicity is a main concern for who applies it or the environment.