I have about 7 second intro and it is rendering about 6 hours and 30 minutes, what can I do, to have shorter rendering
Every aspect of the time that a render takes is highly dependent on the setup of your scene, your render settings, and the hardware that you are rendering it with.
Are you rendering with Blender Internal, or Cycles? Blender Internal takes a long time to compute things like reflected light and ambient occlusion, and is limited to being able to render only on the CPU - and only on a single thread of the CPU for certain calculations. Cycles on the other hand, is much faster for computing reflected light and ambient occlusion, and can take advantage of a hardware acceleration on modern video cards to get hundreds of time better performance than rendering on the CPU.
The complexity of your meshes will effect the number of bounces a light path takes, and the complexity of your materials will effect the work that needs to be completed for each bounce. Try working through some tutorials on optimizing your renders.
For Blender Internal: http://www.blenderguru.com/articles/13-ways-to-reduce-render-times/
You may also be giving each CPU thread or GPU too much or too little work to do with your render tile sizes. For CPU rendering, smaller is better - Something like 32x32 or 64x64 may work well. For GPU with Cycles, I have had good luck with 240x240 on my 780Ti's, and 240x120 on my 980's, and generally decent performance at 120x160 on all of my cards. You may need to explore which tile size works best for your scene setup. Here is what some other people have learned about tile sizes:
Even with computers thousands of times faster than what was available years ago, patience is still a virtue. I run a render farm at home with 4 machines with 3 modern video cards each, but due to the complexity in my scenes, I have to set my renders to run on all of my boxes overnight to render about 5 seconds of full HD video.
You will also get answers closer to what your looking for if you can be more descriptive of your scenario, of your scene setup, your render settings, and possibly even provide some screenshots of the scene in your blend file when you ask questions moving forward. Good luck!
I'm assuming you're using Cycles if it takes so long to render. Try following some of these tips...
GPU Rendering: You can try rendering using the GPU if you have a CUDA (Nvidia) or OpenCL (usually AMD) GPU. Go to File > User Preferences > System, check under "Compute Device." If you have a CUDA or OpenCL GPU, you will have an option to switch to GPU rendering. If you have an Intel GPU like me, well...sucks to be you (and me).
Portal Lamps: If you have an indoor scene with windows, you should use portals. Portals are invisible area lamps that tell Blender where the camera rays should go. Put area lamps over all your windows, and check the "portal" option for all the area lamps.
Tile Size: The default tile size (64x64) is optimized for CPU rendering. If you use GPU rendering, set it to 256x256. Go to the render tab in the properties editor and expand the performance section. Tile size should be visible.
Indirect Clamp: Scenes with lots of caustics will produce lots of indirect lighting. This makes your scene both noisy and render slowly. Set your indirect clamp to 5 for starters if this is you.
Reduce Samples: You should know this by now, but you can reduce the samples to render your scene faster. You don't need 1000 samples for every scene. I only use 100-400 samples for my scenes, usually, 250 is fine.