VISA & ENTRY: Most EU/UK/AU/CA/NZ visitors enter under Visa Waiver Program (ESTA, 90 days max). Apply online for ESTA at least 72 hours before departure (15 USD fee, 2 years validity). CURRENCY: US Dollar (USD). Credit cards accepted almost everywhere — Visa and Mastercard universal. Some places require pin or contactless. ATMs everywhere. Tip in cash sometimes preferred. LANGUAGE: English (no official language at federal level). Spanish widely spoken in California, Texas, Florida, NYC, NM. Many cities have multilingual signage. ELECTRICITY: 120V, 60Hz. Plug type A & B (flat 2-prong + ground). Adapter needed for European/Asian devices. TIPPING (essential): - Restaurants: 18-20% - Bartenders: 1-2 USD per drink - Taxi/Uber: 15-20% - Hotel housekeeping: 2-5 USD/day - Bellhop: 2 USD per bag - Tour guides: 10-20% DRIVING: Right side. International Driving Permit recommended (some states require). Most rental cars are automatic. Speed limits in mph (1 mph = 1.6 km/h). Tolls common on East Coast highways (E-ZPass or rental car toll pass). INTERNET: Free WiFi at most hotels, cafes, libraries. T-Mobile, AT&T, Verizon prepaid SIMs available at airports. HEALTH: Travel insurance essential — medical bills can be huge. No universal healthcare for visitors. Urgent care clinics 100-300 USD per visit. ER visit 1000+ USD before insurance. SAFETY: Generally safe for travelers. Standard precautions in cities. 911 = emergency (police/fire/ambulance). Stay aware in major cities at night.