Door policy exists for a reason. Clubs want a certain crowd, and your outfit is your first impression. Get it wrong and you're waiting in line for nothing. Get it right and you're in. Here's the practical advice that actually works.
The Universal Rules
No athletic wear. No shorts (unless you're at a pool party). No sandals or trainers at most high-end venues. No overly casual — think "dressed for a nice dinner" as your baseline. Collared shirts for men at most places. Dress or equivalent for women. When in doubt, overdress.
Las Vegas
Vegas clubs are stricter than you might expect. Collared shirt and dress shoes for men. No sneakers. No shorts. Women have more flexibility but still need to look intentional. The pool parties are more relaxed — upscale resort wear works.
Monte Carlo and Europe
Europe is stricter. Jacket and tie for the casino. No trainers at Jimmy'z. The standard is higher. When in Monaco, dress like you're going to a wedding.
The Psychology
Door staff are looking for people who fit the room. That means looking like you belong. Confidence matters. So does being in a group that looks cohesive. One person underdressed can get the whole group turned away.