Write down a list of material you have. Break the material up into categories. Jokes should be categorized by subject matter. Stories should by separated by genre and by subject matter. Selling our jokes and stories is about finding markets that accept the type of stuff you have to offer. You should know your material before you attempt to sell it.
Locate markets based on the type of work you have. There are plenty of greeting card market listings online, as well as greeting card websites that offer writer guidelines. These companies often purchase jokes for their greeting cards. Other markets for your work include novelty websites, which also have writer's guidelines on their websites if they accept freelance material. Not all companies do. If you're selling stories, the "Writer's Market" is a book -- there's a membership website as well -- database of markets that purchase stories. The book gives contact information, tells you what to submit and how to format the submission and how much you will be paid. There are also a number of market listings online that can be used free of charge.
Write a market beside as many of your jokes and stories as you can. The markets and work you choose to pair up should come from reading market guidelines to determine the type of work a market accepts and placing that market with the best suited of your work. Pair up as many of your jokes and stories with a market as you can. The more work you have in circulation, the better your chance of getting published.
Submit the jokes and stories to the markets you select. Follow specific submission guidelines of each market. The markets give you guidelines because they want submissions delivered as instructed. Ignoring those guidelines can result in your work being ignored or tossed in the trash. With each submission, include a brief letter introducing yourself and indicating that you are submitting a joke or story for consideration. Make the note short and thank the addressee for taking the time to consider your work.