Video surveillance cameras tend to be located in a high position, typically out of the average person's line of sight and usually too high for it to be reached without standing on something or using a ladder. This prevents people from tampering with your equipment. Video surveillance cameras are often clustered in a 'nest' to give the viewer a 360-degree view from a certain point.
You will want to place your cameras in areas that you particularly want to monitor. This includes property entrances, high-crime areas and parts of your property that are likely to be destroyed or otherwise damaged. It is important you do not place video surveillance equipment in areas where personal privacy is expected, such as bathrooms and dressing rooms, as this is illegal if the people being filmed haven't given their consent.
Most of your typical CCTV and similar video surveillance systems are legal in the USA. However, the general rule is that video cameras should be kept out of areas where personal privacy is expected, including bedrooms and locker rooms. Also, although video surveillance is legal, recording audio that goes along with the surveillance footage is illegal, unless you have obtained consent from the persons being filmed. Also, your video surveillance system should not encourage illegal activity in any way--this carries criminal penalties.
If you are going to install surveillance systems in your company building, it is recommended you inform all employees. This is just in case there are any issues or objections that employees may have that might cause legal problems in the future if not dealt with promptly.
In general, if you intend to install a covert video surveillance system--that is, not tell employees or people who enter the property they are being watched--it's probably a good idea to check with your local law enforcement officials first. It's better to be safe than sorry, and it's much easier and less costly to make sure what you're doing is legal first, than having to deal with the legal repercussions in the future.