Difficult allotment crops and getting advice

This time of year I always tell myself to follow as much advice as possible, but invariably I always miss something. So this year, I vow to pay attention!

My areas of difficulty or concern:

• Carrots - always get carrot fly!
• Brassicas - never get very good cauliflowers or get club root problems
• Pumpkins - never grow beyond a tennis ball and plants are too small
• Sweetcorn - success last year but more fluke I think
• Celery - love it but ahhhh nothing doing total fail each year, may try this year
• Fruit trees - planted new ones (Cherry, Pear and Apple) last year so pruning is a mystery!

Good sources of advice:

• BBC: http://www.bbc.co.uk/gardening/basics/techniques/ (great pages of advice)
• RHS: http://apps.rhs.org.uk/advicesearch/ (really good month by month guide)
• Got an iPhone - get the RHS APP (I unfortunately have a HTC) http://www.rhs.org.uk/News/RHS-Grow-Your-Own-iPhone-app
• Your blogging friends and the Twittersphere (a useful lot indeed) e.g.  http://allotment65.blogspot.com/