carrot seed, poor germination

I see the thread 'Can't grow carrots' but I can't even get them to germinate.
I have wasted several packets of seed this year and what I think has happened is:

early spring - too cold at night
mid spring - too cold at night AND too dry
late spring/summer - damp & dry alternating.

and yet, I sowed the round carrot 'Parmex' in a tub and got good germination.
so I tried another tub and got almost nothing.

Can anyone give a good guide to better germination?

I've also had some problems, last year (my first) I sowed into compost filled drills under fleece and had great germination. Too much really as I'd sowed too closely which gave me problems later. This year I sowed very thinly and then pulled the tiny seedlings to thin out. The trouble is the other seedlings keep keeling over, I water and force compost around them to make them stand up. I have gaps everywhere, perhaps next year I'll just scatter the seeds over the whole bed and take what I get. 

• Don't sow too deeply
• keep the seed bed moist
• consider a sprinkle of slug bait - they may be coming up and feeding the wild-life

I don't do this as there's not been the need with my soil but:

• take out a drill say 2" deep and fill it with water allowing it to drain into the soil
• add a line of damp compost to the bottom of the drill
• sow seed onto the compost at the bottom of the drill
• cover with a fine layer of fine soil or more compost being careful not to compact this

Water - keep watered but not drowned or washed away.

Here's hoping it works for you 

ive had problems with carrots germinating this year, \i have put it down to weather conditions, I just think it been too dry....

Snap, everyone on our lottie site has had trouble with carrot germination this year and beetroot has not been that great either, been watering with a fine rose on the watering can, did not help,