How to adjust the bad picture from nikon d5100?

How to adjust the bad picture from nikon d5100?

You can't.

You need to reshoot this time using the cameras light meter and some basic photographic techniques.

The is a huge misconception that most if not all good photos come from post production.,

Back in the day when we shot transparency film, what we got was what we got, no second chances.

If you use basic photographic techniques used for decades, you will rarely need to do anything after you take the shot

In addition to the last answer - learn to take photos in RAW - these can be edited post shoot!

It's true: you can't make something out of nothing. It may be something that's salvageable, but you won't be able to turn something "bad" into something beautiful in post. If you wanted specific ideas of how to adjust a certain element of the photo, post a link to it here and we may be able to help. Just keep in mind that you can't take a fuzzy photo and make it sharp. That's a common problem with new photographers, and the only way to fix it is by re-shooting.

Also, as far as RAW images go - you can also edit JPEG. RAW gives you more finely tuned control over the image (especially when using programs like Photoshop and Lightroom.) If you aren't planning on wanting that control, however, and you're satisfied with editing JPEG, just shoot JPEG. RAW takes up a lot of space. It can save you sometimes if you really over or under expose, but when you shoot JPEG your camera adds some contrast and slight color adjustments on its own.