The most important part of a meditation practice is sitting down to meditate. Doing it right is not so important. It is only practice. The practice is watching your mind. As you watch your mind in meditation, you open yourself to possibilities. You don’t know what you will get out of it, but you sit anyway.
Meditation is good anytime of day or night. It is good to find a time in your routine to practice meditation, because if you don’t practice regularly, you rarely will decide spontaneously to meditate. If you practice regularly, you will often spontaneously meditate. You might find yourself sitting on a bus, or in a waiting room, or at your desk, or in a meeting, and you will follow your breath and practice being aware of your awareness. You may consciously focus on listening to what somebody is saying. You may focus on a spot on the floor. You may focus on your phone and act like you are getting sucked into technology, when, really you are doing the opposite. That kind of spontaneous meditation grows out of a regular practice.
Mornings and evenings are good times to practice meditation. In the morning, meditation will help you wake up. At night, it will help you go to sleep. It is convenient to attach your meditation routine to your sleeping routine, because that is the time you already dedicate to resting and letting your mind sort itself out. It is especially convenient to add meditation to your sleep routine if you experience problems sleeping. If you have an active mind, that may keep you from falling asleep, or it may wake your from your sleep. If you have problems falling asleep, meditate before bed. If you wake in the middle of the night, get up and meditate then. If you wake up early in the morning, meditate then. Try any or all of those.
Finding a regular time to sit for a set amount of time is the basis of a meditation practice. What you do when you sit, is to practice paying attention to your attention. Then, when you are not meditating, you will find yourself using the skills that you practiced.