It is best to set a routine and stick to it so that your baby knows what to expect. Even if it is not working right away. Try starting an hour and a half or two hours before bed time. Do an activity that will tire your baby out. We run around the house playing and tickling or taking a nice walk. Then we have a snack to make sure their bellies are full. A healthy one, like applesause or bananas. Then we have bath time, giving them time to play after they are all clean then we go into our oldest's room together, get dry and dressed. Then we have story time together snuggling together and reflecting on our day. Both of mine are set in this routine and we haven't had a problem with bedtime. Every once in a while children have growth sperts, have just figure out something new they can do, get new teeth, or just don't want to miss what you are doing. The best thing is if your baby doesn't go to sleep just keep putting them back to bed if they are in a toddler bed. If it is a crib maybe you can try some soothing music for them to listen to to drown out any outside noises that could be keeping them up. If your baby wakes up in the middle of the night, don't go in right away. See if they are able to settle themself. If they do get really upset then take them to get a drink, change their diaper if needed and put them right back to bed. They will get the hang of it after a few days. If when you put your baby back and your baby has a fit and you can't leave the room, then sit in there but do not talk or make eye contact with your baby so that they know your their but they need to settle themselves to sleep. Our son 19 months just started in his toddler be because he was climbing out of the crib and sometimes I have to sit in his room until he settles himself and goes to sleep. Don't beat yourself up about it though. Remember your baby doesn't stay your baby for long so loving and cuddling, and getting your baby is fine. This is just a phase.