too tense to glide

My swimming lesson referred to me being 'too tense' when smimming and this was echoed my someone who had given me and a friend a few years ago when I asked him for a tip when I bumped into him last weekend. I have been trying to work on this (as I write I feel that inbility to relax/ need to maximise effort in most things I do is a personality flaw that I could do with losing in other aspects of my life as well as swimming).

Anyway, other tips:

1. Need to reach with stroke (and try and glide - see also 2)
2. Need to maximise propulsion from first and last section of stroke in water
3. Need to keep head from twisting up when taking a breath
4. Need to stop left foot from twisting (when taking a breath)

Felt very tired after my lesson (concentration?). Will see if I can reduce strokes per length (c30) and more importantly reduce time for 2 miles from 1.5hours recorded a few weeks ago next time I visit the pool (Wednesday/ Thursday next week). Must also remember to pay coach for my lesson!