Sticker charts can work. It depends a lot on the child though, some children are very motivated by a sticker chart and others just don't care.
With age, it also differs, some children have the capacity to understand at just 3, others not so much. Keep it very simple and be consistent.
When you want to implement it, just explain what it is and how it works. Initially, you should give stickers reasonably freely to motivate him and so he can see the result i.e. stickers building up and a prize at the end. Once he understands the concept and is motivated to earn stickers you can gradually make them harder to earn.
The key thing to remember is that sticker charts only work for behaviour that they can control i.e. they can choose to be good and earn a sticker. It's not necessarily going to be effective if the sort of behviour you're talking about is night waking or something else out of his control. At nighttime/when he's half asleep he isn't going to be able to say 'oh I won't cry because I won't get sticker tomorrow morning'.
Also, it always more effective to address the cause of the behaviour, so look at why he is doing what he's doing (he is anxious?scared?just not tired?needing the loo? etc.).