How do I improve Flexibility?

I don't do stretching as much as I ought to, just when I am out for my running, about a mile in. I know I should stretch at the end too, but I am too lazy. The improvements in flexibility were gradual, so I only notice it once in a while thinking, oh, I couldn't have kicked this high a few months ago...
Are you doing anything except stretching in those 30-45 min sessions? That's kind of a foreign concept to me. Maybe try yoga?
Good luck...

What do you want to achieve?

Flexibility is a funny thing, unless you are unable to live a normal life without pain or restriction, you are probably flexible enough.

To put it another way, unless you are suffering pain, or unable to do a certain action, whether that be in everyday life, or for a sport, your flexibility is probably adequate. There seems to be this idea that everyone needs to be super flexible, but in reality you need to be as flexible as you need to be (obvious statement is obvious). Now if you're a gymnast this is going to be more than a runner which is going to be more than someone who just lives a normal life with no sport.

Moving away from that, stretching may not be the answer, often a muscle doesn't need to be stretched, it needs to lose some tone (how tense\active it is, not the popular use of the word). This could be caused by inhibited reciprocal muscles, weakness at end range of movements.

It may also be that the muscle has scar tissue and adhesions, and so massage and self rolling can help.

Finally muscles may not be the issue at all, and it may in fact be a joint restriction, for example you can have the longest most relaxed calves in the world, but if the talus is stiff or has a bone spur, your ankle range of movement will be limited.

I know I've not really given any answers here, but hopefully there is some food for thought.

Yoga. It will change your life.

Thank you all for your kind answers. Yes - Yoga or something like it seems the best. What I wanted to know, however, is how long does it take. I know you would not get instant results and I have to be patient. But how patient?

Could anyone share their personal tid-bits? Like - "It took me 4 weeks to touch my toes", or "I took 8 months to do the split". I just need to benchmark - so that I don't lose patience.

Thank you all.

I started doing yoga once per week about three months ago. Took only two sessions to feel like I had drastically improved hip flexor flexibility, which is why I went to begin with (to help with my running). Biggest benefit was learning specific poses that I can use any time for post-run stretches.

Thank you all for your kind answers. Yes - Yoga or something like it seems the best. What I wanted to know, however, is how long does it take. I know you would not get instant results and I have to be patient. But how patient?

Could anyone share their personal tid-bits? Like - "It took me 4 weeks to touch my toes", or "I took 8 months to do the split". I just need to benchmark - so that I don't lose patience.

Thank you all.

Don't expect major results straight away, but you'll definitely notice little changes bit by bit, which is really exciting. I'm only 22, so I an't give you any anecdotal evidence that will necessarily benefit you, since our bodies and flexibility levels are probably entirely different. However, if you keep at it (particularly if you try and practice a few things, outside classes at home), you will definitely see results.

I practiced yoga twice a week for 6 months and started seeing results. When I first would lie on my back and stretched my leg up, it was pointing straight up. After 6 months, it was at an angle. Now two years later, my foot is right over my face! And it doesn't hurt! And I've also brought down my blood pressure. Stick with it for at least six months and you will see results, but you can even see them before that. Make sure you find a yoga practitioner who is licenced.