Hitting the road or the air for the holidays this year? 
Here's a few things to keep in mind when packing: 

Checked baggage weight limits - Be sure to check and weight that bag before you leave home. The easiest way I've found to weigh a bag is to weigh yourself, weigh yourself holding the bag and the then subtract. I also use a handheld luggage scale that you attach to the handle and then hold the bag off the floor. 

Consider how you are getting any presents home - I  typically take a large suitcase that is checked, a smaller suitcase for a carry on and then pack in the large suitcase a collapsible duffle bag that lies flat. This way I can check the smaller bag on the way home and use the duffle as the carry on. 
The Liquids - Be sure to follow the 3-1-1 rule and have your quart size baggie easily accessible at the top of your luggage. Formula, breast milk and juice in quantities greater than 3.4 ounces or 100 milliliters are allowed in carry-on baggage and do need to not fit within a quart-sized bag.You should put those liquids in a separate bag for inspection. 
You can bring a ice pack - as long as it is still frozen solid - to keep your formula, breast milk or juice cold. For more resources on going through airline security with children - check TAS's blog:https://www.tsa.gov/travel/special-procedures/traveling-children
 What about the presents?  

The wrapping - The best strategy I've found is to go to the dollar store and stock up on bags and tissue paper. I pack the bags and tissue paper in the middle of my suitcase where they are less likely to get wrinkled. Then we I get to parent's house - all I have to do is unpack the bags and place the presents in them. 

The presents - I fit as many presents as I can into the carry-on. This way I don't have to worry about it. I try to pack any of the presents that clothes or books into the checked bags as they are less likely to trigger additional security screening. Do not pack toys with the batteries inside them. Be sure to TAPE any on/off switches to the OFF position before packing.  Some toys have a demonstration mode that is on when you buy them. Double check. 
The batteries - TSA has a good blog on what to do with batteries. http://blog.tsa.gov/2013/06/travel-tips-tuesday-safely-packing.html
What am I missing? What are your go-to holiday travel packing tips?