Many more proposals are submitted for talks, tutorials, and posters than can be accepted. You can increase your chances of getting accepted if you follow these recommendations:
Fill out your outline and biography completely, but concisely. The outline and background information often are used to eliminate proposals during the first cut, so incomplete details may be a cause for early rejection of a potentially great talk or tutorial. Don't let this happen to you!
If you've given a talk, tutorial, or other presentation before, especially at an earlier PyCon or another conference, include that information as well as a link to a video if available. If you have never given a talk or tutorial at PyCon, you will dramatically increase your chances of having your proposal accepted if you link to a video of a presentation you have given somewhere else.
Provide a link to source code, articles, blog posts, or other writing that adds context to the presentation.
Include quantitative data where possible. For example, if your website serves 500 million users per day, then include that detail in your outline.
Clearly identify the audience for the talk or tutorial. Is your audience an experienced Windows developer, or a junior Linux, web developer, etc?
Pair up with an experienced speaker/presenter. This is especially true for tutorials - if you are new, or nervous about presenting a talk or tutorial, sometimes teaming up with an experienced speaker can help you not just put together a solid proposal, but they can co- present with you at the conference.