First and foremost, what are your top tips for getting the littlest subjects to cooperate?

Schedule the photos to be taken when your kids are usually at their happiest during the day, whenever that might be. Before or after nap times, when they get home from school, etc. Forcing them to take photos when they are tired or hungry isn't going to work out well. If this is too unpredictable, picking a location your kids love helps a lot. They will be excited to be there and bring out those natural smiles!

With children, especially, the candid moments can be gold. Any tips for capturing a more relaxed family shot?

Candid moments are the best! I find this is mainly up to the photographer to be quick and present. As a family, the best thing you can do is to just relax and not be self-conscious. Let your kids be themselves and those sweet moments you love will come!

When choosing a professional photographer to shoot family photos for a holiday card, what should one look for?

Look for a photographer that knows how to use light well and captures the moments that you find unique.

And what about DIY tips? For those who decide to go it alone, any advice for fail proof amateur shots?

Whether using your camera phone or a DSLR, find the light where your kids look best and the photo will look great.

What about location? Do you suggest outdoors or indoors? A particular time of day?

Outdoors or indoors are both great options. It just depends on how you want the photos to look. The most important thing about inside photos is to be sure the room has nice window light or your photographer can properly light the photos with equipment. Overhead lighting is always bad. For outside photos, morning or afternoon is the best time to take photos when the light is at its best. In the middle of the day the sun is too high and the light can be too harsh.

And any suggestions when it comes to dressing the whole family?
I think this is a very personal preference. Matching can be sweet if that is your style. However, I personally prefer when everyone dresses in their individual style. One tip is to dress within the same "dress code." If one kid is in their new favorite party dress, don't dress the other in PJs. Keep the dressing similar across the whole family for some consistency. Whatever you decide on, just be comfortable.

Are there any absolute don’ts when it comes to capturing the perfect holiday family photo?
I am not opposed to bribery to help motivate your kids to cooperate, however wait until the end of the shoot to give your kids their reward. If you cave too early they will just want more and be distracted. If it's candy you have promised it will ultimately end up on their face and clothing. Or worse they are chewing gummies with their mouths wide open in every photo.