Pick something as your grounding or home base, maybe breathing or a constant feeling in your stomach. Breathing is the easiest one since we all have it and has a rhythm to it. Pay attention to the breath, count breathing in one, breathing out one, breathing in two, go until five and then again from one. Its ok if you forgot the number start from one again. Each time you realize something from outer world has got your attention a memory a thought… just gently and kindly bring yourself back to the home base. Eventually you'll get better at it but just needs patience and love
Don’t try to make your mind blank and try not to get upset with yourself if you can’t focus or visualize on a certain aspect. I believe that is the point of meditation- you’re disconnecting already. Just enjoy the time you have with yourself and allow your mind to learn about itself- if you seem to be losing focus, why? If you’re focusing on an event or emotion, why? Be kind, breathe, and let go of any judgement you have during the process of learning about yourself! It’s easier said then done, I still yawn for the first 5 minutes every time!