With regards to food, one must understand that there are separate laws for different types of food. The requirements for animals are that they must chew the cud and they must also have split hooves in order to be kosher. One famous animal known for not being kosher is the pig. It is treif because it has split hooves however, is doesn't chew the cud. In the Torah there are 4 examples for treif animals, one is the pig and the other three only have one of the requirements to be kosher but they have not been discovered until today. When killing an animal is must be done in a certain way called schitah. This process is done by an expert called a shochet and it is the only way that an animal can be killed to be considered kosher. The idea of schitah is to kill the animal with one hit from a perfectly sharp blade so that it causes the animal minimal pain and in the most humane way possible. Once the animal has been slaughtered all of the blood must be drained and certain parts of the animal may have to be removed as they may not be allowed to be eaten. After this, everything is packaged and a stamp called a hechsher is put on the package.
The requirements for fish to be kosher is considerably more simple than animals as fish must only have fins and scales to be kosher. This means that shellfish is forbidden as they do not have scales or fins and are therefore not kosher. There is not a specific process with the killing of fish and therefore fish can be bought at any shop as long as there is a clear marking of what the fish is however a hechsher is not required. Birds and poultry also have laws and requirements. Any birds of prey are forbidden to be eaten and only the eggs of a kosher bird can be eat otherwise the eggs are not kosher. Eggs must also be checked so that they do not contain any blood and if they do, they must be discarded. Insects are not kosher at all and can not be eaten under any circumstances. This means that all vegetables and fruit must be checked so that there are no insects inside. Sometimes, an insect may not be kosher however what they produce may be allowed to be eaten such as bees. They are considered not kosher however the honey they produce is kosher.
When discussing kashrut in regards to clothing there are also rules and requirements that must be met. This includes clothes not being made with blends of wool and linen together. If there is an item of clothing that does wool and linen then it is not suitable to be worn and is labelled shatnez. Again there is no reason for this and it is categorised as a chok because there is no reason for the rule. Women have a certain dress code to stay modest in public (tzniut) as in the Torah it says that jews 'shall walk modestly'. This means that women must cover their collar bones, elbows and knees with clothes that are not skin tight. Women are also not allowed to wear trousers and must wear skirts. Men must also dress modestly and appropriately in public. Men must also wear a kippah at all times and women when married must cover her hair in public.
There are also rules that have been put in place when dealing in business and trading goods fairly. When using equipment to measure goods it must be done accurately as the Torah states that jews 'must not falsify measures of length, weight,or capacity. You shall have an honest balance, weight, a dry balance and a liquid balance.' There is also a law not to deceive anyone when trading so that there are no hidden costs that the buyer is not aware of and you can not lie to a buyer when selling goods as well. All packaging must be correct as well and you can not put any false details on a package either.