Regular short periods of mindful meditation can work better than occasional long ones. If you struggle to find the time, you might want to decide on one or two routine activities which you will try to do mindfully each day.
Try to build your practice slowly. Remember, you’re learning a new skill so it’ll take time to develop. Most people find it hard to sit and meditate for long periods of time at first, so try to do a few minutes and gradually build up to more.