How to get crisp photos?

I have a Nikon D40. What are some tips so I get crisp photos?

Do I need a tripod?
Are there any settings that improve the sharpness?

I have noticed that in some of my photos, certain areas seem super focused and clear, and other areas are a little blurry… I know it's the way the camera is focusing in more on the closer objects. Is there a way to avoid this? I haven't found a setting that tells my camera how to focus on an area vs. The closest object.

I seriously do not get why everyone started using the word crisp instead of sharp. Next we'll be hearing mushy instead of blurry. As to your question, a general rule is this. A wider aperture will give a shallower area of focus with the main subject sharp and the background blurred. A narrow aperture will give a deeper area of focus, such as that of a landscape photo. FYI the larger the aperture number or f stop the smaller the aperture will be.

Look in your owner's manual about setting the focus points. You can select any of the focus points that you see in the viewfinder. Most pros set to the center point. When you have the center point selected as your focus point, you place that point where you want focus to be, half press the shutter to achieve focus, and while holding the shutter button half way down to lock in focus, you then recompose the photo. Once the photo is properly composed, you then press the shutter button the remainder of the way down to take the photo.

Remember, just because the center point is set as the only active focus point does NOT mean you put all your subjects dead center in the frame, as that is terrible composition. Focus, lock, recompose, take photo, … That is how the majority of pros use the auto focus feature.

Using auto focus is fine, but you do NOT want to allow the camera to choose WHERE it focuses. Those are two very different things.

As said in the other answer, your aperture will control the depth of field to determine how much area in front of and behind your focus point is in focus.

You may not know it, but your actually asking around 10 different questions here.

Reasons why my images are not crisp

1) camera shake, use a tripod.

2) Low light that makes a slow shutter speed necessary giving moving subjects a chance to blur in the picture.

3) Lighting, flat shadowless light will make for flat shadowless images, highlights reveal - shadows define.

4) Front or rear focusing, calibrate your auto focus if your camera allows it (yours doesn't).

5) Dump the 'protection filter', see 4) and 9).

6) Learn about depth of field, the close you are to the subject the narrower the DOF becomes.

7) Choose the correct aperture, aperture also controls DOF, the wider the aperture (lower the f number) the narrower the DOF becomes, the opposite is also true, the smaller the aperture the wider the DOF, but the slower your shutter speed will be, see 2).

8) Lighting, so important it's worth mentioning again.

9) Is the lens clean? You don't need to polish lenses, they are designed to absorb light not reflect it so mustn't be shiny, but they should be free from grease.

10) High contrast lighting will give more 'perceived sharpness' as will high contrast subjects.

11) Make sure you camera is focusing where you want it to, not where it thinks you want it to.

I'm pretty sure your talking about DOF, see 6) and 7).

A tripod would help, but there's much more to your problem and I can't tell much with out some examples. Send me some.

Use a faster shutter speed to avoid motion blur. If slower shutter speed is used, try using tripod.
Put the ISO down as well. ISO causes noise and grain in photos.
The use of flash could help, as a low ISO and fast shutter speed could cause under-exposure.

Editing obviously helps as well. Try download GIMP for free, or using Photoshop, if you already have it.