Using the Jiffy 7 plugs, I normally stand them in tepid water until they won't swell any more. Use warm water, it speeds up the process, and they don't seem to get too wet.
I tend to use the windowsill propogators for them, you can pick them up for around £7 delivered from Amazon or Ebay (ebay is cheaper at the moment). What I tend to do is use two sets of labels, and put them across the width of the propogator. That way if you've got 18 jiffy 'pots', you can have 6 pots of 3 different types of seed - I wouldn't try any more than that, otherwise your propogator will be full of seed labels.
When potting on, I buy different coloured square pots (again ebay), and matching seed labels, only bother writing out one label, it saves time when cleaning up when everything's in beds or baskets. You can re-use the pots and labels year after year. I also use the square pots and shuttle trays rather than the round ones, as you can get 3 trays of square pots into a coldframe or pvc greenhouse, whereas you can only get 1 or 2 trays of the round pots in.
Small seeds scatter a pinch of them over the top & cover with vermiculite, medium & large ones push into the centre & leave them to it. When they germinate, hoick them out of the propogator & into a small (and I mean small) pot, label individually until they're big enough to go into the coloured pots outside in the coldframe or greenhouse.