I've got a 8.0 Megapixel camera (The camera of Samsung Galaxy S2 smartphone).
I need to take pictures of the product, and I want to make it look as best as can be!
It's a notebook, and it even looks better in real life than in pictures (I don't know the right word: I think the pictures are distorted. The pictures look "dotted")
I thought that such a camera would be good even for professional use!
How should I take photos? And what software should I use to edit them (easily)?
First, make sure your camera is set to highest resolution and quality supported, the galaxy S2 has a 8 mega pixels camera but it can also be set to take lower resolution pictures, down to 640x480 (0.3 mega pixels) and at that low resolution the pictures are really mostly unusable.
I believe what you call "dotted" is noise, the way to reduce noise is to have lots and lots of light
Your best option is to take the picture outside in bright but cloudy whether (you need sun-level brightness but direct sunlight doesn't make things look good).
If you don't have cloudy whether you can try to take the picture outside and place some diffusing material (white fabric or semi transparent white paper) between the laptop and the sun.
Your second best option is to place the laptop near the biggest window you can find - but not in direct sunlight.
And, sorry to tell you, but your smartphone is not a pro-level camera, to get clean pictures in anything but full sunlight you need a bigger sensor, a bigger sensor also needs a bigger lens and so you can't fit a such a camera into a cellphone (pro photographers carry those big cameras with them for a reason)
Without seeing an example of the kind of things your suffering from it's hard to give specific advice, but I can make some general statements. Firstly, I don't think any professionals would ever use a phone's camera for any commercial work, for the simple reason that the sensor is smaller than it could be whilst remaining economical. Small sensors are much noisier than sensors with larger photocells, and also have less light-gathering ability so need a higher ISO to be used, introducing more noise.
Using the number of megapixels a camera as a guide of its quality does not work. Here's a quote Ken Rockwell's excellent article The Megapixel Myth which is a far better explanation than I could write myself (Emphasis original).
The megapixel myth was started by camera makers and swallowed hook, line and sinker by camera measurebators. Camera makers use the number of megapixels a camera has to hoodwink you into thinking it has something to do with camera quality. They use it because even a tiny linear resolution increase results in a huge total pixel increase, since the total pixel count varies as the total area of the image, which varies as the square of the linear resolution. In other words, an almost invisible 40% increase in the number of pixels in any one direction results in a doubling of the total number of pixels in the image. Therefore camera makers can always brag about how much better this week's camera is, with even negligible improvements.
This gimmick is used by salespeople and manufacturers to you feel as if your current camera is inadequate and needs to be replaced even if the new cameras each year are only slightly better.
One needs at least a doubling of linear resolution or film size to make an obvious improvement. This is the same as quadrupling the megapixels. A simple doubling of megapixels, even if all else remained the same, is very subtle. The factors that matter, like color and sharpening algorithms, are far more significant.
The megapixel myth is also prevalent because men always want a single number by which something's goodness can be judged.
Unfortunately, it's all a myth because the number of megapixels (MP) a camera has has very little to do with how the image looks. Even worse, plenty of lower MP cameras can make better images than poorer cameras with more MP.
I'd definitely recommend reading the article in full to gain a proper understanding.
In terms of the problems you're facing (and assuming this is a noise problem), I'd be trying to increase the amount of light in the scene (and thus decrease the ISO), but you'll have to be careful about blown highlights, where some small areas of the picture are far brighter than the rest of the picture. You want a good even light over the whole image.
I normally use a window ledge for the best light, and if the product is small enough, use a piece of A4 paper underneath and let it curve up the window to give an impression of an infinite white background. Photography is all about the light, so make sure there is plenty and is not casting harsh shadows. Use another piece of white paper as a reflector if needed.
Be sure to clean the lens cover: Most people just turn on the camera app and shoot, but a phone is handled almost in a ruthless manner, compared to even the most humble camera, so chances are the "front element" is blurry due to fingertip grease. Remember that in case of phones this front element is just a protective glass (or polycarbonate, etc) so don't be frantic about it: any cotton swab will do the trick.
If it's a notebook chances are it's black. ( Is this the case? ) Most cameras are calibrated to meter light so they achieve 18% gray (more or less). But the case of a black object taking up most of the scene may get the cameras metering a little confused, trying to make black look gray (light-wise, not color-wise speaking). This is why I suggest also:
All these parameters are reachable from the default camera app's setting menu in the Samsung Galaxy S II.
Almost any cameraphone, and even point and shoot cameras will yield grainy photos in low light, and for these devices, even a typical office may be low lighting, that they automatically try to overcome, some by increase exposure time (tends to produce moved or blurry photos) or increasing ISO sensitivity (Tends to produce grainy or "dotted" pictures). This is why I recommend using a fixed ISO. But if you shoot in low light, the phone will increase exposure time, so I also recommend to use some object to support your phone while taking the photo (Since you cant use a tripod, strictly speaking) Any object that keep you from shaking the phone will do: like a glass bottle, a coffee cup, a pile of books... etc.
Borrowing the suggestion given in another answer: Use a ply of thin white cardboard to create an infinite background, this trick alone will make your product look a lot better, but also gives a good reference to calibrate your settings on the phone since it HAS TO LOOK WHITE, not gray, not bluish gray, not orange-ish gray, etc. (Since it's a product shot, not a creative picture) The background should look gray only where the product projects its shadow.
Another thing people don't seem to mention, especially for situations that require working with low-light, is to stabilize the camera.
You can try your best to hold your hand steady, perhaps bracing it against something sturdy.
Or you may find better luck placing your smartphone in a stable location and using the timer function that many typical camera apps offer. It can take a little practice, but will help at least get the best out of situations where it's tough to avoid low light levels.
