The quickest way, strangely enough, is not through anything you do with your mind. The quality of your meditation settings, when you’re just getting started and when you’re out of practice looking to get back into it, is greatly enhanced through the use of ritual.
Hold your horses there, you don’t have to build an alter and burn some sage. I’m mostly talking about the little rituals you do every day to stay healthy and sane. Do some light exercise, take a shower or bath. Eat something light so hunger doesn’t intrude on your session. For exercise, I like a brief, but intense cardio session, preceded or followed by a nice long stretching session, try it both ways and see which you like.
Basically the idea is you want to shut the body up by taking away everything it can complain about, because guaranteed once you sit there and try to clear your mind, anything you didn’t take care of, will be something you now have to tell yourself to ignore once you’re on the cushion. Which is easy if you’re used to it, hard if you haven’t done it in awhile or not at all.
If you’re just starting to learn then the skill you’re trying to build up is called access concentration. You start with an object in mind, something pleasant, benign, and not super-interesting. I like picturing a candle flame in mind. Set a timer for ten minutes, sit comfortably, I like to use a recliner, and put the object in mind and try to keep it, and only it, there until the timer goes off.
The quality of your meditation will be pretty bad in the beginning. Your mind will wander. The candle will disappear and you’ll have to remember to put it back. The idea here is to progressively work towards a state of mind where the only responsibility you have for the time being is this one object. Give your mind ONE job to do.
This is why the timer, it removes the responsibility from you to determine how long you should be sitting there. If you don’t have the timer, then you’ll be constantly contending with time pressure. The exercise removes body pressure, the shower / bath removes comfort pressure, eating (light snack only!) removes hunger, and the timer keeps your immediate mind from thinking about the outside world. On the cushion, the object keeps your mind from wandering, and being gentle with yourself keeps you from beating yourself up when it does wander.
It’s not a binary thing, meditation isn’t. Think less about whether your mind is completely clear and just concern yourself with the object at hand.
If you do this right, your mind will start to wander “anyway”. But it’ll be a different kind of wandering. The flame will stop being a flame and it won’t feel right trying to hold onto the shape. You’re still concentrating on the object but the object itself is changing form, seemingly all by itself.
This is what the Buddhists call dhyana. Access concentration is the foundation, once you can achieve that, dhyana states come naturally afterward. Exploring these is the process of concentration meditation. From here, there’s a choice you can make, you make this choice by whether you start thinking, processing, and internalizing what you’re seeing. Or you can continue to stay ‘still’ and only concentrate and witness what your object turns into or happens to be.
The former is called insight meditation, and it’s how yours truly prefers to meditate. Concentration meditation is more ‘vivid’ than insight meditation, it’s how you produce experiences such as out-of-body or astral projection.
If you’re looking for spectacular experiences, keep your conscious awareness focused on that object! If you want to understand it better though, start thinking about it before you get up and move around because your memory of the experience starts disappearing the second you break the state!
I lump all this together into what I call “trance” state, and I’m usually a kind of low-grade trance at all times, just waiting for me to inculcate a deeper one. Do seated meditation long enough, and the experiences start happening randomly outside of them.
There’s tons more tips, tricks, and advice that’s outside the scope of this answer for me to give, so allow me to point you to Daniel Ingram’s excellent book: Mastering the Core Teachings of the Buddha: An Unusually Hardcore Dharma Book - Kindle edition by Ingram, Daniel. Religion & Spirituality Kindle eBooks @ Amazon.com.