If you are new to meditation you need to pay attention to a few points:
First of all the duration of the meditation is not really important What is important is being consistent in your meditation practice.
So instead of trying to meditate for an hour or more for a few days and then taking a few weeks of what you really want to do is meditating even for 5 10 minutes a time but meditate everyday
Simple is best. There are so many meditation techniques find one that works for you. When you start of simple is always the best.
If you dont have to remember a lot the better you can ease into your meditation practice.
When you are practicing meditation, starting a practicetry to be consistent at what time you meditate, so for instance if morning time is good for you try to meditate at the same moment in time every day
If you happen to have a life where you work in shifts or you run around different times and different days then practice your meditation in the morning or meditate in the evening whenever you can fit it in. But often its more simple to turn a practice into a habit if you can keep consistency in all the areas of the meditation.
When you are meditating try not to do so on a full stomach, if you are going to have a meal before practice have a small meal best more than hour before practice.
If you took a big dinner wait at least two hours. If you don't wait at least two hours after a main meal the blood will be in the digestive system and what's going to happen is you will get tired and sleepy.
When you are practicing meditation you should be very relaxed but very alert and you wont be able to do that when your drifting away to sleep.
When you are sitting it is important that the back bone be erect but the body be at ease.
In most cases meditation practice is done on the floor but if you have physical disabilities or severe problems of stiffness in your hips or lower back maybe you better start by sitting on a chair and that is entirelyok but if you are sitting on a chair try not to be sitting on one of those confortable nice chairs.
The reason is your back will bow into it, you will want to sit on a chair that is very erect at a straight back so the spine remains up right.