There are many ways to meditate, and many ways it might benefit you. But none of that is going to happen if you don't actually do it. So the single most useful tip for meditation and mindfulness is the one that will help you to keep your practice going. And it's this: have friends who meditate.
Pretty much everything in your life is going to try and stop you from meditating and being mindful. There are so many other things that you need to do, and so many things that you want to do. And then there are all the things that you don't really want to do, but find that you can't stop doing, like scrolling mindlessly on the internet. And your own mind doesn't help - when you think you might meditate, it suggests something else that would be more fun or more useful right now. And if you do sit down to meditate, it won't shut up: You've got so much to do...What's the point of this...I'm bored....When is it going to be over?....How about we just get up now; it's been long enough. And finally, the other people in your life might not be much help. At best, they might be vaguely supportive but not really understand what you're trying to do or why, and at worst they might be vaguely hostile, because they think it's silly, or a waste of time that takes you away from spending time with them, or doing the dishes.
So what you need is to create a life that is somewhat supportive of your practice of mindfulness and meditation. And the aspect of your life that has the power to be the most supportive is the people around you. Surround yourself with people who also practice, or have even just one friend who does so, and you've got a powerful countervailing force to all the things trying to stop you from practising.
Buddhist monks have known this for a very long time. That's (presumably) why they live together in monasteries, supporting one another to keep on practising. If you live in a monastery, everything around you reminds you that you are meant to be practising mindfulness and meditation. And Everyone around you is doing it too. You feel like you're wasting time if you don't meditate, rather than if you do.
I'm not suggesting that you go and become a Buddhist monk, but you can easily avail yourself of this same kind of support. If you are wanting to start a meditation practice, see if a friend wants to do it with you. Arrange to check in every day and talk about your practice. Not only will you feel like you're accountable to someone, but you'll make your practice that much more rewarding. We are social animals, and meditation is solitary and often boring or otherwise not that much fun. But if it becomes the subject of a daily conversation with a friend, you might be that much more motivated to do it. Or, if you don't have a friend who wants to meditate, find some new ones. Find a meditation group that meets weekly, or sign up for a meditation course. One way or another, find an opportunity to make your meditation a way to connect with others. You don't have to go to a monastery, but perhaps you can bring the monastery to you.