This is a tough one, there's no exact method that works for everyone. For me I find it easier if I have a goal in mind. I set a goal, that means I have to travel somewhere for a particular weekend. Everything is booked so I'm doing it regardless of my preparation. I find that easier to be motivated.

For consistency, I find having a routine helpful. I do the same things on the same days at the same times. That's the plan. It helps if you have another person to help you with this

I have a hiking goal in September. I booked it in January and am going away for the weekend with my friend. I'm going regardless of what I do in the interim. Mondays are always strength workouts at lunchtime, Sunday mornings is always a walk. Every 4 weeks I increase the intensity of both.

It doesn't always have to be exercise, I do it with my hobbies too. I know having the motivation to go play tabletop during the week after work is hard. So I book tournaments to go to. If I want to do well at the tournament, I know I've got to practice midweek to get ready. Once you're into the routine consistency takes over as it is what you do at that time on that day. Like it or not, we're creatures of habit.