What would be a good topic for a presentation?
By presentation, I'm going to assume that you are giving a speech to a group of your peers. That helps a lot, because your peers are likely interested in the same stuff that you are. It also helps because they are likely sympathetic to you, and/or eager to hear what you have to say. That is way more preferable than speaking to a hostile audience or an audience that is completely apathetic to anything that you might say.
Assuming your audience is what I stated above, choosing a topic becomes easier. Pick something that you already know a lot about and/or something that you like talking about. That does a few things for you. First, if you know a lot about your topic, you can spend more time on the actual presentation and less time researching. Second, if you know a lot about your topic, it lets you share personal experience and anecdotal evidence. You can personalize the presentation to yourself. Third, if you are excited to talk about your topic, your audience can see and feel that. They become better listeners and provide you with a powerful tool -- positive feedback during your presentation.
If the format is wide open to you, choose to give an informative presentation or a persuasive presentation. If the former, pick something you know a lot about to begin with. If the latter, pick something that you feel passionately about. It's easier to sell an audience on something you care about.
I teach public speaking, and I always do an example speech within each genre for my classes. When I was a teenager, I built a motorized skateboard. I attached a chainsaw motor to my board because pushing is lame. My informative presentation is often about my board and how I built it. I loved the thing, and I know a lot about it. Plus it gives me a big visual aid to draw attention away from me. It makes me feel like fewer people are staring at me. For my persuasive presentations, I like choosing restaurants. I live in Southern California, so Rubio's Fish Tacos are a staple here. I love them. It's easy for me to talk about all the reasons why Rubios is so much better than Jack in a Crack (Jack in the Box) or Toxic Smell (Taco Bell).
Informative and persuasive presentations can be combined as well. Let's say that you love video games . . . and Play Station is your platform of choice. You could start your presentation by giving a little history of the Play Station. It's creators, development, and changes over time are all possible points of emphasis. Then you could transition into why it is a superior platform to its competition.
The best advice I could probably give you for topic selection is to pick something that you frequently use. Pick a place that you go to a lot. Or like to go to. Pick something that allows the easy use of a visual aid. All of those things help you know about your topic and feel excited about it. You might not want to give the presentation, but at least the chosen topic easily lends itself for you to talk about.