Do you sometimes see pictures in which the sun has these nice rays and they're exactly looking like we drew them in kindergarden?
Yes, me too, and i always think "it really makes a good photo look great". The sunrays, together with the lensflares, give your image instantly that kind of warmth and coziness - even if it's a winter wonderland like this.
So, how can you do it yourself?
First of all, anybody who has a camera with a manual mode can do it! The only three things you need is control over shutterspeed, aperture and ISO.
Small aperture
The key setting here, is to set a small aperture (big f-stop number) like f/11 or higher. Maybe you've already noticed yourself, if you take a picture with the sun at a large aperture like f/2.8 for instance, your sun is looking like a diffuse white area and the lensflares are undefined and superbig.
But if you instead set your aperture to a value of 8+, your sun takes shape. Notice that the smaller your aperture, the finer and longer will your sunrays get and the more angled your lensflares will become. The effect will vary depending on the lens you use, but try around between f/11 and f/22 and you should get great results.
And there's another thing to take care of...
Mind your exposure
A common piece of photographer's wisdom is "don't shoot into the sun". In my opinion, this is only true for people who photograph in Auto-mode. Yes, if you're shooting directly into the sun, your camera is literally overwhelmed by all the light and is likely to underexpose your photo because it tries to compensate.
But there are several ways out of this issue:
1) Use your camera exposure-correction
You can manually set the exposure settings, so that your camera overexposes in regard to its normal settings, which in turn balances the underexposure.
2) Use flash
If you're shooting a model or an object reasonable close to the lens, you can always use your flash to adjust the lighting conditions. If your focus is set properly, your camera will automatically adapt.
3) Shoot in HDR
This is what I did in this image. To get instructions on how to shoot HDR, have a look at this post. You basically shoot 3 or more photos of the same frame with different exposures, so that your computer can later compose the three exposures and pick the best parts of each shot.
And here are the Exif-data:
ISO 100, f/11 at three different shutterspeeds. Here are the three original pictures:
Now have fun shooting sunny pictures ;)