Preparation:
Before you begin, make a resolution to simply be present for your meditation practice, however long it is: five minutes or five hours. Turn off your phone, doorbell, all distraction, and be alone in the space where you are going to meditate.
For those who believe in some form of Divinity, invoke the form of the Divine that appeals most to your being. It could be a deity, a Guru or any inspirational being; it is entirely your choice. Ask this being to help and guide you during your practice. No formal methods of worship or long preparation is needed, a simple heartfelt bow/thought/prayer is perfect!
Posture:
There are diverse opinions on the best posture for meditation. The great masters at whose feet I have learned have taught me that when it comes to posture, only two simple things count: it should be stable, and it should be comfortable. If both of these conditions are met, then whether you sit cross legged, in some asana, on a chair, stand up, or even lie down if that is best for your body – everything works perfectly well. If the body is comfortable and stable, it will not distract the mind from the goal of meditation, and that’s all that is required.
As far as possible, keep your trunk, spine, and neck in a straight line. This helps the flow of energy from the base of the spine, upwards to the crown of the head. Initially, you may not be able to maintain this posture for long, especially if you are not used to sitting erect. That’s perfectly fine. With time, you will find a position where the posture becomes totally effortless, even when sitting for longer periods of time. Bear in mind though, the aim of meditation is NOT to simply sit for longer. It is the quality of meditation that makes the difference.
Other ‘gear’:
Nothing except you is really needed for meditation. If you need something like a pillow, a blanket, a chair or anything else to achieve a comfortable and stable position, then it is totally fine to use those. Avoid using extraneous things like incense, candles, etc: they only serve to distract the mind by feeding the senses.
Time of day:
The times of dawn and dusk are especially conducive to a clam and tranquil state of mind, and are therefore naturally better for the practice of meditation. The breath, which is usually more dominant in one nostril or the other throughout the day, flows equally in both nostrils during dawn and dusk. Also, from a practical point of view, the time of early morning is peaceful, as people are still asleep, and the activities of the day haven’t started yet.
That said, whatever time of day suits your schedule best is appropriate for meditation, as long as you are feeling reasonably fresh and can remain alert and awake for the duration. It is best to avoid meditating late at night just before going to bed, as the mind is likely to be too tired by that time.