1. Find a consenting partner (or partners).
2. Get your partner/s' explicit consent. Give your explicit consent. Compliance is not the same as consent. Your partner/s should be as excited and ready as you are. Don't try to talk anyone else, or yourself, into fucking.
3. Use whatever combination of prophylactics (condom, dental dam, etc.) and birth control (condom, the pill, Today Sponge, etc.) you need to prevent the transmission of disease and/or pregnancy (unless you're trying to get pregnant).
4. Do whatever feels good for you and your partner/s. Communicate as you go to make sure your partner/s is/are still feeling safe and having fun. There's no one right way to fuck—and exploration, even and maybe especially when it's awkward, is part of the joy of fucking.
5. Rinse and repeat. As often as feels right to you and your partner/s.
[For some reason, "how to fuck" is perennially a search term that brings people to Shakesville. Currently, the results bring searchers to Portly Dyke's How to Fuck Up post, which is good universal reading, but I thought it might be nice to provide a post that offered the instructions for which people are actually searching, too.]