IPhone photography advice?

I have an iPhone SE, what are some tips you can give to make an photo look nicer via photo editor or whatever?

Major tip is about lighting when you take your shots. Photo editor is generally used to touch up the exposure, not rescuing images. If you understand the basics of lighting, your photos will turn out much nicer. Case in point, sitting down with a friend for 5 minutes and discussing lighting made her cell phone images much better (went from unusable to keepers). She now directs her subjects to optimize the lighting.

Next, work on composition. Avoid the usual mistakes like trees sticking out of your subjects head, cluttered background (toilet in the background), …

Your decisions that you make prior to taking any photo will have a greater impact on the quality of your photos than any app that you could possibly use.

Your choice of lighting is huge. Take photos under interesting, compelling light as opposed to mid-day sun. Your decision of subject matter matters. Don't take photos of boring, uninteresting things and then wonder why no one likes them. Understand that your composition is a major part of what makes your photos good or bad. Your timing is critical too. Taking a shot because you're there's fine, but waiting for the optimum moment will add a lot to your photos. None of these things have anything to do with the device you are using. For many photos, the gear you use is irrelevant. Just as long as the phone or camera you are using doesn't inhibit you from capturing the shot the way you to capture it, when you want to capture it, then use whatever works.

You have to get the shot right during the moment of capture. No app or software like Adobe Photoshop is going to fix your bad decisions. Consider apps as tools to enhance an already good shot. It's like a good sauce. If you don't cook the steak correctly, then no matter how good the steak sauce is, you still have a poorly-cooked steak.

With that said, Adobe Lightroom mobile is one of the best photo-editing apps for those who take photos with their phones. With it you can adjust the brightness, contrast, color, so that the final image best expresses your personal vision.

Learn photography.

You should always aim to shoot a photo so that it needs very little "editing". Just as we did in the good old bad old days when we shot on film.