BMW
BMW normally puts their tag under the hood on the driver side shock tower. The code is 3 digits and is located on the bottom left corner of the tag. In the example shown you would drop the /7 giving you the code of 354.
Chrysler/Dodge/Jeep
For the most part these codes are located in the driver side door jamb. Generally Chrysler, Dodge, and Jeep codes will be a combination of three letters and numbers beginning with the letter P. In the example pictured your paint code would be PW7.
Ford
Similar to Chrysler, Ford labels are typically found in the driver side door jamb. They have done a great job of standardizing their labels so 99% of the time you will see a label that looks exactly like the one pictured. The paint code will either follow "EXT PNT:" or be directly above it, never below. In this example your paint code would be FL.
General Motors
(This includes Buick, Chevrolet, GMC, Pontiac, and Saturn)
The location for GM paint codes does tend to vary. The most popular location is in the drivers side door jamb. You may also find the code located in the glovebox, in the trunk on the decklid, or in the spare tire well. The code is typically 4 characters long and usually follows either the letter U or the letters WA. For the example shown, the paint code would be U8624.
Honda/Acura
Honda codes will usually start with the letters NH, or the letter R, G, or B. It is located on the bottom center of the decal, like the example that is shown. Generally, the tag will be found in the driver side door jamb. On the sticker shown, the code would be NH638M.
Hyundai
Hyundai will have their paint code located on the top right corner of the decal. The code is 2 digits long and it is usually found in the driver side door jamb. For the example you see, the paint code would be S3.
KIA
Kia is very similar to Hyundai, the decal will almost always be found in the driver side door jamb. On the top right of the decal you should see the word "Paint" followed by a 2 digit paint code. In the example pictured, the code would be EB.
Mercedes-Benz
This one is a little trickier than others. Only because, its a 3 digit code on a plate full of 3 digit codes. You should be able to find this plate on the radiator support under the hood. Typically the code will be on the bottom left corner of the plate. In the example shown we have circled the paint code, which is 702.
Nissan
Nissan paint codes will generally be located in the drivers side door jamb or near the hinge area. Some models you may also find that it is located near the passenger side firewall. The code is usually 3 characters long and can consist of letters and/or numbers. In the example shown, the code would be BW9.
Toyota/Lexus
Toyota, like most other manufacturers, stick their tag in the driver side door jamb. Near the bottom left corner you will see "C/TR:" The paint code will directly follow that. Giving you the paint code of 1C0.