The Magic Sleep Solution.

 Toddler sleeps by London Photographer, Evie Winter

Sleep deprivation isn't the sole preserve of new parents, though I am not sure I have ever discussed it so much than since I had my second baby! What causes it, how to cure it, how to cope with it. 
For Indiana, our second - it was caused mostly by bad reflux. The reflux which stole her newborn days and made them so much harder than it needed to be. When she wasn't sleeping, it was because she was in pain.
So assuming you have dealt with the physical issues and are now in the "acceptance and how to cope" phrase, this are the three things that helped me.

Aim: To avoid sleep deprivation induced mental health problems

1 - Lower your expectations
The worst thing about bad sleepers, is the house will go to ruin. Who has energy for any kind of work on 4 hours or less sleep? Accepting that some things just will not get done, it's okay to let the washing wait, cook a more basic meal - this is survival mode. Anyone who would judge rather than help you, probably should not be around anyway. 
Love is messy, those who truly love you, will help you clean up!

2 - Rule Nothing Out
For the longest time, I was keen to get Indiana back in to her cot. Even though I knew she only wanted to be in our bed. We persisted. 
The day we conceded and got a bigger bed to accommodate co-sleeping, is the day we started to get more sleep. (Every so often, I say "enough, sleep in your own bed", inevitably - no one sleeps so well those nights.)

3 - Connect with your Child
It has been a while since we have been able to watch a film without having to stop half way through to settle Indiana back down, however I tried to enjoy the times with her a little more. I remember one night thinking about a mother I know who had lost her (adult) child, whist a really morbid thought - but it got me thinking thinking about how fortunate I am to have a healthy baby to cuddle. We don't know what tomorrow will bring so appreciate the now.
Bringing it into perspective is about all you can do when nothing else works.

It is worth noting with our oldest, we did let her cry a bit before she drifted off. With Indiana having reflux, I couldn't be sure that her crying wasn't her being in pain - so now we have a low threshold and rarely let them cry for more than a min during the night. 

For me there is no true magic solution, but changing my own attitude, like with most things can often improve the situation.