Sure, here are some tips for your trip to Phuket, Pattaya, and Bangkok:

Best Time to Visit:
The ideal time to visit these places is during the cool and dry season between November and April.

Route and Accessibility:
Phuket, Pattaya, and Bangkok are well connected by flights, buses, and trains. From Bangkok, you can catch a short flight or a long bus ride to Phuket or a 2-hour bus ride to reach Pattaya.

Altitude and Acclimatization:
These places are at sea level, so no worries about altitude sickness.

Accommodation and Booking:
All three places offer a range of accommodations from budget to luxury hotels. It's advisable to book your accommodations in advance, especially during the peak tourist season.

Clothing and Essentials:
Pack light clothing due to the tropical climate. Don't forget your swimsuit, sunblock, and insect repellent. Also, carry a universal adapter for your electronic devices.

Health and Safety:
Avoid tap water and choose bottled water instead. Be careful about street food and choose to eat from places where food is cooked fresh. Be aware of your surroundings and keep your belongings secure.

Local Etiquette and Respect:
Thailand is called the "Land of Smiles". Be polite and respectful. When visiting temples, dress modestly and remove your shoes before entering. Also, never disrespect the king or images of the king; this is a crime in Thailand.

Enjoy your travel to these beautiful places in Thailand!