Because Egypt is massive, intercity travel requires planning.

Domestic Flights: EgyptAir offers frequent, affordable daily flights connecting Cairo to Luxor, Aswan, Hurghada, and Sharm El Sheikh (usually 1 hour). This is the safest and most efficient way to travel long distances.
Trains: The Watania Overnight Sleeper Train is a popular, nostalgic way to travel between Cairo and Luxor/Aswan. It saves you a night of hotel accommodation and provides dinner and breakfast in your private cabin.
City Transit: In Cairo and Alexandria, Uber is safe, extremely cheap, and eliminates the need to haggle with local taxi drivers over fares.

Egypt is a conservative, predominantly Islamic country. Both men and women should dress modestly when outside of beach resorts (covering shoulders and knees). When entering mosques, women will be asked to cover their hair with a scarf, and everyone must remove their shoes.

The Art of Baksheesh: Tipping is a deeply ingrained part of Egyptian culture. You will be expected to tip for almost everything—from bathroom attendants and hotel porters to temple guards who point out a good photo spot. Always carry a large stack of small denomination notes (10 and 20 EGP bills) to hand out easily.

To avoid the infamous "Pharaoh's Revenge" (traveler's stomach), never drink the tap water in Egypt. Use bottled water exclusively, even for brushing your teeth. Avoid ice in your drinks at street-level cafes, and stick to fruits that you can peel yourself (like bananas and oranges).

That said, Egyptian food is hearty and delicious! You must try Koshary (a carb-heavy mix of lentils, rice, pasta, and spicy tomato sauce) and authentic Egyptian falafel, known locally as Ta'ameya, which is made from fava beans rather than chickpeas.