Jamaica has the one of highest murder rate in the world. Some areas of Jamaica, especially cities such as Kingston, experience high levels of crime and violence. In addition, it is best to avoid certain parts of the island at night. Marijuana (ganja) although cheap and prevalent, but is illegal on the island. If a Jamaican try to sell you drugs or anything else, just tell them you have been here many times before, and you are not interested.
Jamaica is not a suitable destination for LGBT tourism. In the cultural and legal, LGBT are to be abhorrence, and many Jamaicans are hostile toward this people, especially between two men. If you insist on going, the most advisable way is avoid displaying affection to people of the same sex in public.