How do you make high quality pictures on photoshop?

I have pictures, but they're like grainy, kind of. And I wanted to know how to make them look crisper and in HQ on Photoshop CS3. Or if you can't do it on Photoshop, could you tell me how in general?

You're not going to like this response, and I'm not trying to be flippant or cute, but take better pictures. Really. You can do some smoothing and sharpening on Photoshop, but you are not going to get really high quality results from photos that aren't high quality to begin with. It's the nature of digital images: they are made out of pixels, and you only get so many pixels in the image. Think of them as the data or information in the picture. If there isn't a lot of info to begin with, you can't add info and make it better. You can always REMOVE info easily, but you can't make something from nothing, and you can't really make high quality out of low quality.You didn't say where you go the pictures, if you took them with a camera, what kind of camera, etc. If you are using a digital camera, the best thing to do is take the time to learn how your camera works, what settings to use for the conditions in which you are shooting, and so on. Also always make sure to take photos at the highest quality setting and largest file size your camera allows: the idea is to get as much info in the image as the camera can record.Pro photographers will tell you to "get it right in the camera" meaning take the best shots you can. Don't depend on Photoshop to fix it for you. Good photos depend on your eye and your understanding of and skills with your camera.