I am in no way an expert but I have been meditating on and off since I was around the age of 20. After a longer break I have been getting back into it since 2010. I find that meditation helps me to be more present in the moment and thus in life, have a more positive attitude and focus on the stuff I find important. Try it and you might find similar benefits.
Here I have collected some advice and links to the most relevant research on meditation (another good summary can be found on Wikipedia). Most of the techniques I have tried have a Buddhist background but this has nothing to do with religion, more with how our mind/body works.
My main meditation technique is Vipassana with Anapana as a fallback when I'm unfocused or have troubles relaxing. As an introduction I also recommend Sam Harris (well-known, american author on science/reason/morality/religion) answer to a question if he still meditates.
Because you can pick up the technique and go much deeper when focusing intensely on learning it for 10-12 hours per day for 10 days in a row. Since this gives deeper experiences and insights you are more likely to continue meditating daily than if you slowly try to build up to the same experiences over the long-term. So the reason is educational; it is easier to motivate and actually do a long-term change in your life and create a new habit if you can as quickly as possible experience some of the benefits that you would otherwise only get after long-term use.
I'm not looking for a religion in the traditional sense of the word. In relation to this question I think the following two quotes are relevant:
"Believe nothing no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and common sense." - Buddha (Siddharta Gautama)
"The religion of the future will be a cosmic religion. It should transcend a personal god and avoid dogma and theology. Buddhism answers this description. If there is any religion that would cope with modern scientific needs, it would be Buddhism." - Albert Einstein
During a 10-day Vipassana retreat you do not have access to your mobile phone, computer, any books, pen/pencils or paper. You also do not look other meditators in the eyes and have no bodily contact. This enables you to go deeper and get more out of the meditation and learning experience. I had no major problems with this aspect. Sure, it felt a bit weird to basically avoid other people that lived close to me for 9 days (on the 10th day you can talk and touch again) but I also felt a respect for their process and did not want to disturb anyone. On the 8th day I felt really bored and would have really liked some external input from a book or computer. I felt I was finished with the course and had learnt what I could. But once I got over that day, the 9th and 10th days were actually my strongest and most rewarding. So, yes, it was not easy but not as hard as I believed to basically be without external inputs.
Before I did my 10-day retreat the thing I thought/worried the most about was that I would not get enough food. You basically have breakfast around 7am and then a light. vegetarian lunch at 11am but then only fruit and tea at 5pm. Since I had the idea I need to eat before going to bed I was worried I would not get enough sleep. As it turned out I had no problems with these aspects. The food was enough and with 6 hours of sleep each night I felt energized when waking up. Partly, I felt this was because my mind/body was working more efficiently after a few days in deep meditation but it could also have been because we did very little physical exercise/movement during the retreat. I took a few brisk walks and did some light bodyweight training every day but nothing more.
It was both one of the best and one of the worst days of my life. I definitely think they could have helped preparing us more for getting back to our normal lives and situations. It can feel very different and at some point I got afraid something had gone wrong. But by basically quickly setting into a normal routine while trying to take things/life a little bit lighter for a few days I soon felt back to normal (but with the new insights and techniques) within 2-3 days.
According to a recent study (Chiesa and Malinowski, "Mindfulness-Based Approaches: Are They All the Same?") there seems to be differences, yes. All mindfulness based techniques aim to reduce negative emotional experiences. But for classical Buddhist mindfulness meditation (BMMs) traditions (such as Vipassana and Zen) these are secondary health benefits while they are the main, or only, focus of modern mindfulness-based interventions (MBIs such as mindfulness-based stress reduction, MBSR, and cognitive therapy, MBCT). The MBIs are also focused on specific disorders (such as depression) while traditional BMMs view the suffering as common to all humans. The large majority of empirical studies focus on MBIs and there is consistent evidence suggesting the potential benefits of MBSR for a number of physical and mental disorders, including cancer, chronic pain, rheumatoid arthritis, fibromyalgia, psoriasis, multiple sclerosis, and HIV. However, it is not clear to what degree these benefits actually come from mindfulness and if results for one technique can be generalized to other techniques and/or disorders.
You can either start with some other meditation techniques such as some of the mindfulness meditation practices or Anapana. They are straightforward and simpler. There is also a very good book on Vipassana meditation by Marshall Glickman called "Beyond the Breath". It gives a good overview of what Vipassana is and how it works and also is an excellent intro to Buddhist thought in general. However, in one of the book's chapters Marshall presents Vipassana as it is thaught in the S. N. Goenka tradition. I find this description good once you have taken a course, as a reminder, but I would not recommend only learning Vipassana from a book (I bought the book after taking the course). The risk is that you will not have as strong experiences if you start experimenting at home, and thus you are less likely to actually continue to practice. But there are many ways to find your way so it might work for you.
I use Insight timer from Spotlight Six Software to keep track of my meditation. It has beautiful tibetan chime sounds to mark the start and end of your meditation. You can also set up specific chimes at different times to mark different steps in your meditation. I really like it.