Hi Bri,
My son is 16 months old and we struggled with bedtime. Some nights he would go to bed at midnight and still wake up at 3 am crying and wanting to get up.
What worked for us was an absolutely concrete bedtime routine. And I mean *concrete*. Absolutely no variation whatsoever. Every night at 7:45 he takes a warm bath. In the bath we brush his teeth and have a fun time playing quietly. After his bath we put on his diaper and pj's, and I pick him up to tell his daddy goodnight and give kisses. Then we walk throughout the house waving night night" to things he recognizes. We tell everything goodnight, then I pick out two books. We go to his room, turn off the light and leave the hall light on, read his first book, kiss it goodnight, read his second book and kiss that one goodnight - then Mama gets goodnight kisses and I rock him to sleep. He has a "sleepy song" I sing to him, and then I lay him down.
I know thats super detailed - but I'm telling ya - it works! He cried a lot at first and it was really hard not to give in (we were breaking him of two habits - staying up too late AND taking a bottle before bed) ....but now its wonderful.
We do this at naptime and at bedtime. Anytime he is going to sleep, we use that routine. He has it memorized and it gives him a lot of security. He doesn't like it, and does protest a bit still (saying "No night nights" or "No this" meaning 'No books'...) BUT the wailing, screaming and staying up at all hours is over!
I will say this though, if crying it out becomes the norm, you definitely need to be present after 10 minutes or so. No matter what, I will go into his room and rock him for a few minutes to calm him before laying him back down. No talking, no lights, and no leaving the room - but definitely a moment or two of calm and solace. A temper tantrum will easily turn into panic for a child this young as they don't remember things well and eventually, what started out as Mommy saying good night turns into 'I'm stuck in a dark room and no one is coming, where is my mom?" ....Jo Frost has a great method for dealing with this. Thats where I got the basis for our new routine.
Good luck!