Hi Ella. Hope this helps.
Here are a few tips we have found to be helpful.
Make sure you have the correct consistency for your sprayer. Most of them require paint to be thinned.
Prime the sprayer and test on a large piece of cardboard or other surface.
Light coats of paint.
Keep it moving.
Clean immediately at the end of use.
If you are talking about a paint sprayer.... I wrote a post on how we painted our outdoor furniture with one >>> https://www.homeroad.net/2016/07/using-paint-sprayer-on-outdoor-furniture.html