I have a scene in blender of an office. It has chairs, tables, computers, and so on. I would like to know how I can render this scene faster as I am planning to make animation inside the office and dont want the render to take forever. I know of sampling,resolution and most things in render settings. I have also heard of render passes or rendering using layers. Any ideas?
What rendering engine are you using, Cycles? What's your setup like, how is your scene lit? Assuming it's Cycles:
You can't really just "render faster" for the most part. You can optimize your scene but speed mostly depends on the performance of the machine, desired quality level and scene complexity. A faster renders generally come at a price of sacrificing quality.
That being said there are a few setups that are slightly faster to calculate, and additionally there are numerous ways you can optimize your scene so that it generates less noise. With less noise you could achieve desired level of quality with less samples, you could then reduce the number of samples and finish rendering faster.
Generally speaking Cycles likes big and easy to find light sources, the smaller a light source or lamp is, the harder to reach or the more hidden or indirect it's contribution is to the scene is, the harder to render it gets, producing noisier output that needs more samples.
Try searching the internet for "Reduce cycles noise" or "Optimize Cycles render" and you will find plenty of tips about it like the ones bellow as an example:
You could try baking your textures. By baking your textures you get cycles to render one high quality texture and use it with one sample in the final animation. One limit is you will want to use a static light source. See the results of this blenderguru tutorial.
Depending on how you want to animate, you could render one static image (or several from different angles) of the office, then render an animation of just the characters moving and composite them onto the static image/s. The render of only the characters will be very fast in the transparent areas around the characters - 70-80% of the image?
You can even combine the two ideas. Use the baked scene to quickly render a fly through animation of the office and then use it like a live video and composite the character animation over the top. Rendering the two separately allows you to render shadows with the characters and composite them onto the background. You can find several questions here about shadow only rendering and compositing.
First off, BlenderGuru has some good tips in his 4 Easy Ways to Speed Up Blender Cycles article. The tile size mod is especially effective. In addition, if you make the edits in 7 Ways to Get Rid of Fireflies In a Blender Render, you will be able to drastically reduce the render samples (speeds up render).