Seeing the number of posts association with omg my fermentation is stuck, I have been investing some time to establish patterns. There are a few basic ones:
1) reusing a yeast cake (preferrably washed after 2-3 brews) is a great technique to speed up fermentation
2) creating a hot environment for the wort+yeast initially really makes a big difference with almost all kinds of beers (and I do this WAY above the prescribed temperatures without off flavors - but I do ratchet it down after a day or two).)
3) a starter -i've seen enough yeast issues to know that a starter - even the day of makes a big difference.
--> todays anecdote: i had a nottingham liquid yeast from a previous batch in the fridge and a 2006 nottingham packet that has never been refrigerated and kept in a hot garage. One of those I got from a buddy who gave me all of his gear. I started both of em.. My cold notty from just a few weeks ago didn't go but my 06 started just fine.. So my point is that you never know. Some people are having problem with that same strain 2011 batch... which eeek.. I have a few packets of. So the purpose of the starter is to see how active the yeast really is. I'm sure my cold batch will do great - but it will take 48 hours as it is hibernating.
Now for the more ingenious tricks. So temperature is key. Yeast vigor is very important. So i have a new trick I just started. To acclimate the yeast to the temperature - and avoid the dreaded temp shock that may kill yeast or retard it... I get a cup - which I sterilize (plastic 16 oz type) and I use that for my starter. I let the wort cool (another note on that later) and then I re-sterilize the cup and place the whole cup in the wort when I get BELOW 90 (preferrably mid 80s). So now the yeast gets to the temperature of the wort - and I can do this with the fermenter covered. It's a beautiful thing.
Wort cooling mcgyver style.
I get a bunch of water bottles - leave 1 inch of head room and freeze em. I then I use a bigger tub to cool my wort - placing the pot right into cold water. Here is the key. Within 5 minutes the water gets real hot to the touch. Dump it and add more water. Make sure to cover the wort so that there is no contamination. If you do this 2x in the first 30 minutes - you're likely to be able to picth in 1 hour or less by using the frozen bottles and cold water in your third bath. it's great - you now have extract beer that can be made in 2 hours or less.
usually my next step is to get the wort +pitched yeast in a "hot room" to speed up the yeast process. I often need less than 8 hours to start a very active fermntation using this technique. That said, some of my slowest fermenting beers are among the best. So - these speed techniques are more for efficiency than flavor.