I've been making my own bread for a few months now but am unable to consistently make a nice light loaf. 3 times out of 4 it's too heavy. How can I get it to rise better? I've done the following with no consistent results:

1/ good kneading for 10 minutes until nice and rubbery
2/ enough water (I thought at one point my mix was too dry but I've been through the whole range of wetness through to sticky tonight
3/ Using 3 or 4 teaspoons of newly opened yeast
4/ Using good organic bread flour
5/ letting yeast get going (fizzing) before adding to flour
6/ keeping mix warmish whilst rising (or not!) - I can see when it's risen too fast when there's a false 'crust' on top

Funny thing is the odd time it rises beautifully and I get a nice light loaf.

Help! I do so enjoy doing my own bread...