If you have a new habit that's not time-specific and doesn't take too long, try to do it first thing in the morning. It will not only get done (and be harder to forget), but the feeling of accomplishment can help your state of mind in achieving other tasks throughout the day. For me, lifting weights for the day takes 5 minutes to do a simple workout, but once it's done I feel like I've gotten something significant achieved and that makes me more motivated during the day.