Traveling away from home with a baby can be fun and at the same time it can be hard. The keys to making it as pleasant as possible are mindset and preparation. Try your best to balance replicating home routines (within reason) and being flexible (schedules, moods, energy levels won't be perfectly in sync with how they would be at home — do your best to roll with it!)
Pack ahead (at least the night before, sooner for longer trips); this is a game changer because it makes travel day less stressful and usually means packing more efficiently (read: packing less stuff) because you put more thought into what you really need
Bring whatever items will help you mimic home & sleep routines where reasonable
Charge electronics (e.g., portable sound machines) the night before & bring chargers
The sheet amount of stuff babies & toddlers need can be stress-inducing in itself
Renting bulky gear at your destination can help you avoidhassle & travel lighter
For places you stay often (e.g., your parents' or in-laws') consider buying an inexpensive additional set of items that get a lot of use, such as highchair, bib/tableware/utensils, sound machine, pack-and-play, etc.
You will most likely forget something at least some of the time. It will be okay.
If you're staying with others (especially grandparents!) be upfront about any hard & fast rules you have for your children, but also avoid nitpicking about little things and obsessing over schedules because this usually creates a more stressful environment for everyone
Enjoy your time away and remember that being in different environments with different people is good for your baby, even if it means straying from your normal schedule! Keep the elements of your routine that you reasonably can, then get back on schedule when you're home