The key for me has always been to be part of a team/club/group that’s in roughly the same ballpark as me in terms of fitness, commitment and goals. Seeing their Strava rides and miles racking up, seeing the messages about people meeting up for rides, going on group rides and being able to gauge where I am against people I know - gives me all the accountability and motivation I need. And having a few days a week where I’m meeting one or more people at a specific time and place for a ride basically makes me close to 100% compliant on doing those rides as the alternative is letting people down. Think I’ve only missed one in the last 6 months and that was when I went to bed feeling fine and woke up for an early morning ride with a headache, sore throat and high temperature.
These days could be virtual as well. A friend has made huge strides in fitness this year from joining an online team who do the WTRL TTT on Zwift every week. Knowing that’s in the diary every week and wanting to progress to doing more pulls, longer pulls, higher average watts, moving up to a stronger team, etc has made him much more consistent with how he trains the other 6 days. Plus having team-mates who notice when he nails a good workout and are commenting on Strava, team meetups, etc.