A fixed wake time is the strongest signal you can send your circadian clock. If you want to go to bed earlier, the first place to start is getting up at the same time every morning. Once that anchor is set, you can training yourself to sleep earlier by moving bedtime back 15 minutes each night, adding morning light, and keeping evenings darker.
This article covers the full day of cues — light, meals, activity, and temperature — so your nervous system gets the message that sleep starts earlier.