Lots of interesting questions and no one answer to fit all of us for each of the bits - surface, schedules, holistic:
Surface:
It is best to mix up surfaces during a running week or a running month
- trails, asphalt, mud tracks, grass, treadmill, and even sand -
though that is not found in Delhi - as each gives a slightly different
workout.
Trails can focus a lot more on mental concentration on the road,
anticipation, ankle strengthening, balance etc, plus some random
movements compared to a more predictable stride length and impact of
road running.
A treadmill is great for giving you the data bang in front of your
eyes as you train to push yourself for a speed or a hill work out.
A manicured grass stretch - if you can find one- is great for barefoot
running.
Running on the side of the road in a place like Delhi where there is a thin flm of dust on the tar is great as it gives you a nice padded surface.
Once a week on the flat road - check out wearing the 'Indian Vibram
one finger' or the Bata PT shoes available at Rs 299/- as that would
help focus footstrike on the midfoot more than anything.
Some info on surfaces is at http://runningandliving.com/GettingStarted/#what
Schedules:
Best to follow a schedule during some periods, specific to an
objective, and other times to just chill and have fun and free wheel
(which by the way is also an objective)
Train for speed, endurance, strength and flexiblity or
for a 5k or marathon or whatever
Loads of schedules are available on the internet and some are at
http://runningandliving.com/KeenRunner/ and http://runningandliving.com/HalfandFullMarathon/
All round development:
Any decent schedule mixes up different types of runs and distances -
based on the objective
And flexibility, strength and cross training
and just to clarify - running is not just a workout for the legs and
heart BUT if you want to be a better runner you need to tone and
strengthen your upper body as your arms play a role in propelling you,
your heart and lungs get a great work out and get stronger, ALL your
internal organs get exercised with the impact of running, and running
uphill, downhill, on trails, sprinting running slow, with short
strides and long strides impacts virtually all your muscles from your
neck to your toes - so mixing it up becomes important - and dont
follow the same routine day in and day out. Variety is the spice of
life - just as in food - so also in running.
Just some things I picked up over time
Enjoy the run