Do you use a pacifier? Do you swaddle still? (If she cant roll over yet. Sleep sacks if she can) These are some of the 5S techniques that help soothe a baby. (Suck, Swaddle, Sideways, Shush, Swing)
Based on your comment about connecting sleep cycles etc, it does seen to me like she's able to self soothe IF she's relaxed and sleepy already. May be that's the gap. You can try experimenting with shorter/longer awake periods to make sure she's tired enough but not over tired. And keep putting her down sleepy but awake. She will fuss. There are a few options for what you can do about the fussing :
- The cry it out (needs rock-hard resolve!)
- Fading method (comfort her and leave for increasing periods of time till she falls asleep)
- Any combination of any sleep training that you find effective
But try always putting her down sleepy but awake. Chances are, she'll eventually fall asleep on her own, with minimal fussing that she wont even need you for. Various sleep training articles on the web claim to achieve this in 15 days, 20 days, etc. But each baby is different, there isn't really a timeline set in stone.
For relaxing her, do you do a bed time routine? Try incorporating relaxing activities like a massage, walking around the house saying good night to things in hushed tones, anything else that relaxes her. (My son finds the hum of the vacuum relaxing - that we get time to clean the house is a bonus!)