Ask for a Shedder
Having an un-cracked lobster plopped down in front of you is intimidating. If it's your first time, inquire about a shedder lobsterone that has more recently molted its old shell. Shedders have newer, softer shells, which are easier to crack into. Note that shedders have slightly less meat than their hard-shell counterparts, though many people prefer the sweeter taste that shedders offer.
Know the Colors
Good lobster meat is red, pink, or white. The redder meat is typically sweeter. You might notice some white, cottage-cheese-like substance on your lobster; this is what happens to the crustacean's blood when it's boiled. You can scrape it off easily, although it's harmless to eat it, too. If you notice a green substance in the center cavity of the lobster, it is the tomalley, which serves as the creature's liver and pancreas. It is often served as a delicacy, both alone or mixed into sauces. One color to avoid: yellow. Lobster meat doesn't stay fresh long (this is why lobsters are often boiled right before being consumed), and bad meat will turn a yellowish, rotten color (and will probably smell foul too).
Use the Right Tools
You'll be given a cracker (used to break into the lobster) and a tiny lobster fork for getting the meat out of the shell. The cracker is for snapping the claws, and to break the body apart lengthwise. After cracking, you will probably need to go in with your lobster fork or hands to grab pieces that are stuck in the corners of the shell.
Eat It Strategically
For hot lobster, start at the tail; this is the piece that will go cold the quickest. Finish at the claws, and the meat will be warm throughout. This tactic also keeps the mess to a minimum since it will be easier to discard unneeded bits as you go.
Garnish to Temp
If you're eating hot lobster, you'll want some garlic butter and parsley on the side. If cold, then try horseradish sauce and a lemon spritz. Either way, minimal seasoning is best to truly taste the specific sweetness of lobster meat.