What sides go best with lobster tail?

Can't go wrong with asparagus.

Couscous.

Not sure on the dessert?

A green salad would be a good side with perhaps a wholemeal bread roll or a slice of crusty wholemeal bread.

Creamy butter risotto, ham and cheese pasta (spaghetti or fettucine), mushrooms, zucchini, baby carrots, asparagus, crème brûlée, chocolate mousse

seasoned rice .. asparagus ... cheese cake

A really fresh crisp salad, and maybe a baked potato. 

Cole slaw and biscuts.

Depends on what the lobster is served as-an appetizer or a main course. If a main course, a light side salad should be sufficient as lobster is a light tasting dish. If an appetizer, not much more than some drawn butter and lemon slices.

Steakhouse Mushrooms, French style Green beans with Peppers, Red dessert wine. Then Chocolate Cheesecake, Black Russians. 

With lobster, I don't serve anything other than drawn butter and slices of lemon. Definitely a light appetizer before and maybe a green salad. Dessert is a wild card. 

anything you want