An employer agrees to hire you subject to a work permit being approved. If the permit is approved, you will probably receive a document to take to an official for processing and the payment of a fee. Upon arrival at your place of employment, you may be required to register with the local police and perhaps pay another fee. If you change jobs you must start the process all over again. Those with special skills, like photographers and ski instructors, have the best chance of success, but I've met Americans behind the bar, in the kitchen, and working the ski lifts.
Wages are good, and many jobs include room and board.
Getting a work permit is usually pretty straightforward once you have a job offer. Send your resume to the larger hotels in resorts like Davos, Klosters, St. Moritz, Zermatt, Grindelwald, and Gstaad. Call the local tourist office verkehrsverein and ask for the numbers of the local ski lift operators. Generally, a European employer who wants to hire a non-European Union citizen must demonstrate that they can't fill the position with an EU citizen. Those with valuable skills stand a good chance of getting a permit, while those in lower-paid lines of work will not get one, except possibly for seasonal jobs in resort areas.