Having proper boating etiquette
It can be a lot of fun to cruise around at high speeds and mess around with personal watercraft but don't forget that there are others out on the water who may not appreciate what you are doing. You can inadvertently cause a great deal of harm to others if you don't pay attention to standard boating etiquette. People do all kinds of things with their boats so make sure you don't ruin someone else's day.
Fisherman can get very angry if you even go near them so if you see people sitting at their favorite fishing spot, approach them slowly if you must. They might have had bad luck all day and finally found a good school of fish and if you fly by at high speed, that school might go somewhere else. This is the same as walking up to someone who is fishing on shore and throwing rocks in the water. It's just plain rude.
Small craft such as rowboats, canoes, and kayaks can really suffer from your wake if you have a large boat or are zooming around near them at high speeds. Canoes and kayaks can tip fairly easily and a big wake can even swamp a poor rowboat. You really need to keep an eye out for these guys because they can be hard to spot if the sun is in your eyes and you could hurt people severely if you happen to ram them. This could lead to jail time if you aren't careful. Respect smaller crafts and give them a lot of room.
Lights are extremely important in the boating world. If it starts to get stormy or the sun is going down, do everyone a favor and turn your lights on. This can avoid all kinds of bad situations such as being rammed on accident or being harassed by local law enforcement.
Above all else, just follow the golden rule and treat other boaters how you would like to be treated. If you had your 80 year old grandmother on board, you wouldn't want a bunch of drunken jet skiers circling you right? Just act civil and everyone will get along great.