Every person and family is different, and every trip is different, but there are some general tips that apply to most trips:
Book early, at least 6 months in advance. You get better everything: lodging, flight connections, rental cars, show tickets, entry times, etc. Some of the most exciting hotels have 2-3 rooms only. Some local flights have 20 seats only. Last minute prices may be cheaper, but it normally is for the rooms and attractions that fill up last.
The best part? The trip may only be a week or two, but now you have 6 months of excited anticipation, reading travel guides and trip reports and watching movies on the topic. You just added so much value to your trip for free!
Remember fax and paper vouchers? Long time ago, you had to work with a home country travel agency, because having the home pro’s talk to the destination pro’s was the only way to make it work over fax. That creates jobs at home, and increases your trip cost. But they all have destination partners who deal with anything that may come up.
Today you can book directly with the local destination agency. Chose one that is personally recommended to you, or has high ratings on sites like tripadvisor. They all speak English, and they will all go the extra mile – because good reviews is the number one driver of their business. And they know the local region very well.
If you are more adventurous, you can book almost everything directly from the provider these days. But it will be a lot more work for you, and the connections in-between may or may not work. If you book through a local agency, they will make the itinerary work, and deal with anything that comes up during your trip.
There is very little value from taking everything with you. Pack light. Even if you have drivers and porters carry your baggage most of the time. Make sure everything you bring has multiple uses, and dress in layers. Get quick drying fabrics, so you can launder them over night in the sink if needed.
Install Whatsapp (or WeChat for China). It’s the most widely used messaging app, and all the guides and drivers will have it on their phone. If you want connectivity beyond WiFi, you need a data plan. If you have T-Mobile in the US, you have global roaming which works in most places. If not, ask your carrier to give you global roaming (may be ridiculously expensive, e.g. with ATT). Or get a local SIM. In most places, it will take less than half an hour. Don’t do it at the airport, do it after you checked in at the hotel, at a local place.