My son started that waking up crying at about 14 months. Doctor told us to let him cry himself to sleep as we were making it worse by going in after him, but that first night lasted 55 minutes!!!!! Sheer agony....
We started a routine that seemed to have worked: An hour before bedtime, we started getting them ready then took them (twins) into our bed with a couple of books and would read to them. No playing or goofing around, just lying there with the books, pointing out pictures, etc. Then we would go to the bedroom window and look for the moon and when we found it, say goodnight to it and they then went to bed.
As infants, when they'd awake about 5am, I'd take them both to my bed, secure the edges with extra pillows, give them their bottles and the three of us would fall asleep. That ended when my son fell off-about 6 months old. (still don't know how he got past me, but I am a sound sleeper most times
)
One last suggestion: My doctor gave me this idea when my son was only 5 weeks old and both nursing followed by a bottle didn't keep him sleeping long:
mix a couple of tablespoons of rice cereal with about a teaspoon of breast milk(or formula if wife doesn't nurse) in a small bowl. It should be the consistency of rice pudding. Put a small amount on a baby spoon and see if she sucks it off. If she does, she can take some. If she rejects it, no. Give her this cereal about an hour or so before bed. If she sleeps longer, she was awaking from hunger. Worked for Daniel. Doctor said under no circumstances should the cereal be mixed into a bottle. If they can't take it by eating it, they aren't ready to eat, period. And yes, I did mean 5
weeks. Kid was a freakin bear about eating