Play calming music to focus or energetic music to pump yourself up.
Make a cup of tea, tidy the area, or add your custom starting ritual.
Put on your gym clothes, get out cooking ingredients or find a quiet place to focus.
Be even more effective by launching other apps (Headspace, MyFitnessPal, etc) as part of your routine.
When starting new habits, our mind will naturally resist the change. Sure, you can overcome it with motivation and willpower for a while but that's a short-term strategy.
A better long-term strategy is retraining our mind to adjust to and accept the new habit as the new normal in our everyday life.
Visualization practice is a mental rehearsal of your routine where you simulate and practice over and over again how you'll start and successfully go through the motions until it feels natural and expected to act that way. Starting this way helps overcome your mind's doubts and resistance to change as well as building up your self-confidence to practice in real life.
And what makes it powerful is that our brain will treat each simulation almost as if we practiced and experienced it. So if one sitting can be equivalent to doing your routine several times, a week of visualization practice can make your mind and body feel like they've been doing it for almost a month!