Check the QEC sleep school in noble park website. They have some audio files that are interesting to listen to. I found them helpful. I don't do everything that way. But it helped.

Tired signs for my bub include

Red eyebrows (I learnt that one at mothers group!)
Starting to vocalize more and with a more forceful eh eh kind of sound
Her arms and legs get a bit flappy too.

Sometimes she looks so very we'd awake. But I know she's tired somehow. I never used to. But it gets easier to recognize.

It's hard work watching and listening to the cry and distress. I just wish she would sleep sometimes cause it feels awful.

Also they have times when the sleep might get worse for a while. Around four months for example. It can take a while. But it goes get better xox