If there is one piece of advice I could give every parent, it would be to establish a solid bedtime routine. Its one of the hardest things to do, but once everyone is accustomed, it can be the biggest life (sanity) saver you have.
When building a routine, I always start by figuring out when they get tired enough to fall asleep, or enough to turn into grumpy kids. Then I make sure they are in bed, routines finished, 20-15 minutes before then. For my daughter, that always meant being in bed by 7:30. My son needed to be in his bed by 6:30. After that point is established, I add something to the routine. For example, we say the exact same thing to my son every night before bed. The preamble can all be changed, but before leaving his room I say, “See you when the sun comes up!”
Once that feels solidified, we add something else- usually story time. Each child gets one story of their choosing, and then I get one of mine. The step before this is teeth brushing and bath time. We do the same things every night, which gives my kids comfort in knowing what to expect.
The few times we have strayed from this routine has not ended well. Usually there are tears, and my daughter fights to stay up. If you plan it well, your routine can be something that is done anywhere, even while visiting family or on vacation. You will be glad your kids fall into that routine when you’re out of state I can promise you! You can always adjust your routine as your kids grow. Sometimes we swap singing for stories. But either way, my kids know it’s time to settle down for the night.