In my experience, flexibility increases from three primary categories: 1. Foods and Suppliments. 2. Movement and Physical Postures. 3. Emotional Releasing and Energy Techniques.
If you do something from all three categories it is likely that you'll have greater results faster. Still, though, doing any of them that you feel is beneficial will likely increase flexibility significantly.
Foods and Supplements
With regard to the first category, this is likely where most people will recieve the most benefits. By consuming foods and supplements which are known to induce calmness and flexibility, we can be assured that we are on the right track.
One of the most powerful and inexpensive supplements for this purpose is MSM. This is a bio-available form of the mineral sulfur which appears to both benefit detoxification processes and break up arthritic-like calcification (hard forms of calcium that are created by virus-like bacteria which create health issues related to inflexability) when taken in high enough dosages. While it can be beneficial in some ways to take MSM in the amount that is listed by the product manufacturer, powerful results have been seen when taken in much higher amounts, between 5,000 and 20,000 mg. The average amount that appears to be recommended by people like David Wolfe, who promotes MSM for many uses, is around 8-10,000 mg worked up to gradually. Still, that amount can be different for each person so it is important to start small and not exceed the amount that you feel is too much.
Another set of foods which are known to increase flexibility and overall calmness and contentment is green leafy vegetables. If you digest them well, increasing your intake of whichever green leafy vegetables you like will give you more flexibility increasing minerals and other nutrients. Many healthcare practitioners promote the consumption of alkaline foods, like green leafy vegetables, for this reason. Alkaline foods, in general, are foods which contain more alkaline minerals like magnesium than they do acidic minerals like phosphorus. Alkaline minerals like magnesium and calcium are said to increase contentment and relaxation along with relieving tension in muscles and other areas.
For people who want to increase their intake of green leafy vegetables, there are three easy ways.
1. Salads - increasing the overall volume and amount of times you eat salad can greatly increase your intake of green leafy vegetables.
2. Green Smoothies - This is probably the easiest way to signifantly increase the amount of green leafy vegetables you eat. You just put one of more handfulls of green leafy vegetables in a blender with enough water to cover them and blend for a few seconds (unless you're using a vitamix or other similar blender where you could put everything in at once) and then put in as much fruit as you want for taste and calories and blend again for around 10 seconds. The finished drink should be somewhat sweet, yet green, but easy to drink. Many people have increased their health by drinking around a liter of this a day.
3. Raw Green Vegetable Juice - If you have a juicer, or eat at a cafe regularly where they make juice, drinking green vegetable juice as often as you are able to will give you a concentrated amount of flexibility-increasing green nutrition, without having to consume as much fiber. The result is a quicker uptake of nutrition.
Other foods which appear to increase flexability significantly include minerally dense foods like Sea Vegetables, Blue Green Algae, Spirulina, Chlorella. and polysaccaride rich foods like Aloe Vera, Noni, and Medicinal Mushroom extracts or mycelium biomass products.
Movement and Postures
Another powerful way to increase flexibility is by moving in ways that encourage contentment and relaxation. Certain postures are also known to help with this. Yoga is one teaching which greatly promotes this ability. By doing Yoga, you can become both more content and flexible.
Letting Go and Energy Techniques
Letting Go of stress and doing energy techniques that encourage flow and vitality is another way to improve flexibility. When we let go, we allow more energy to circulate and flow. This improves our overall feeling-state, but also induces overall flexibility. Many times, it is actually emotional issues which create physical symptoms of inflexibility. Using a technique to let go of feelings is a powerful way to increase our overall sense of vitality. Two powerful ways to let go of feelings are The Sedona Method and EFT.