Seasonal hiring: what is paying well this year?

I am looking at seasonal jobs around Seattle that might lead to something longer. This is my first time dealing with any of this. I would like to avoid a gap in my résumé. Which employers treat seasonal workers well?

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.

Keep a list of supervisors' names. A reference from one of them helped me land my next job.