If you want to play defensively, for instance, upgrade your Town Hall and defensive structures such as walls, an archer tower, mortar, and cannons. If you plan to play more aggressively, you won't want to upgrade your Town Hall as quickly because leveling that up could lead to your armies receiving fewer spoils after successful raids. Remember that you can place certain structures outside the protection of your walls, if they don't provide an advantage to enemy raiders, or as a peace offering if you want to give raiders what they want so that they don't attack you just to access it.