Meditation has done so many wonderful things for me over the years!
I find that for beginners, the questions most asked are when they will start to see the benefits and how much of it you need to do. Well, this is hard to answer. I think starting off with even 5 minutes daily will help you obtain the benefits--this is what the science shows. I can't consciously recall when I started to notice profound changes. I think they were very subtle at first. When we learn to meditate, we learn to take pauses, to observe what is going on with our thoughts but not to engage or judge them. It is in moments of confrontation with others or when others are having a moment, that I feel my meditation training at work. Where I can just take a step back for a moment and not react right away and just observe what is really going on underneath.
Meditation is not a complicated practice; in terms of technique it's very simple. Yet it is not easy to do. For some who are always thinking and find it a challenge to relax at all, it might seem very difficult in the beginning. My advice is to start with just one minute then and the next day add another until you find it easier to do. I use the Insight Timer App which has free guided meditations, lectures, music and a timer.
Remember the goal is not to clear our minds. This is impossible and not the purpose of meditation. The goal of meditation is making friends with your mind. All of us have thoughts that will come up during meditation, even the most dedicated meditator or the Dalai Lama does. You are not doing anything wrong. That is part of the process. Be gentle with yourself.