Meditation practice involves developing three skills: concentration power, sensory clarity, and equanimity. That's it. And we develop those skills as with any other, by practicing them. That's all you need to know and you can turn to the guided meditation practice section and begin the journey that never ends. But you want me to say more.
The Three Skills
Concentration Power is the ability to focus your attention on whatever you deem relevant for as long as you want. This is one of the most fundamental of all human skills. Without the ability to focus your attention where and when you want it, it is doubtful that you can learn much of anything or even function as a living being. Conversely, the stronger your concentration power, the better your ability to learn and function. So no matter what you are trying to do in life, improving your concentration power will make you more effective.
Concentration power can be thought of as existing across two dimensions: spatial and temporal. The spatial component is the range of focus or how big a slice of the incoming sensory stream you choose to cover with attention. For example, you might focus on just the somatic sensation at the very tip of your nose. Near the other end of the continuum you might cover all of visual experience, objective and subjective. Or it could be anything in between. The temporal component is how long you keep your attention directed at a particular sensory event. For example, if your focus range is all body sensations, you might cover that whole range evenly and continuously OR you might allow your attention to move freely within that range, focusing briefly but intently on each sensory event, OR you might systematically scan through the whole body, and so on.
Concentration power is developed by by returning your attention to the desired object of focus each time the attention wanders. It is rather like weight training where each repetition of a movement against resistance increases muscle strength. Each time attention wanders and you bring it back, your concentration power gets a little stronger. The wandering and returning is an expected part of the training.
Sensory Clarity is the ability to detect and untangle the components of sensory experience in real time. There are two components to this skill: sensitivity and resolution.
Sensitivity is the ability to detect ever more subtle sensory events: fainter sounds, whispy body sensations, fleeting thoughts, etc.
Resolution is the ability to detect components withing a previously unitary sensory experience. For example, the sound of machinery might resolve into a low-frequency rumble with a pulsing intensity and a chaotic rattle. Discomfort in the body might resolve into a dull ache with tension flavored by fear or sadness.
Development of sensory clarity rides on increasing concentration power. Sustained attention allows sensory experience to unfold its richness like like the opening of a flower. But it is a bit more than just sustained focus. Within sustained focus there must be a letting go of the need to "move on" to the next event, instead penetrating the sensory experience of the present moment, becoming fascinated with mapping its contours.
Equanimity is deep contentment with the present unfolding of sensory experience just as it is. It has also been described as radical non-interference with the natural flow of sensory experience, complete acceptance, non-resistance, surrender to the will of God, and so on. It is an attitude of letting go of the need to have things be different than they are in the present moment.
It isn't easy to develop equanimity directly. You can "invite" it by systematically relaxing the body and intentionally dismissing judging thoughts. But deep equanimity is something you need to fall into randomly during a state of high awareness. Equanimity relieves suffering so if you fall into it during a state of high awareness, your brain learns to seek equanimity in challenging circumstances. The more often you experience equanimity in this way, the more readily available that state becomes.
So the development of equanimity is largely a function of spending time in a state of high concentration and clarity.
Meditation consists of selecting a focus range, a technique that involves concentration, clarity, and equanimity, and doing it regularly. Regularly means most days. Even five minutes (I KNOW you have five minutes to spare) is infinitely better than none. But twenty would be much better. And forty would be really sweet! You should also try to arrange at least one more intense practice session each year. Ideally this would be a residential retreat of a week or more. But a weekend retreat would do it.