You can find an example of the Bristol stool scale here.
http://en.m.wikipedia.org/wiki/File:Bristol_stool_chart.svgBasically 1-3 are not great stools. These generally suggest an unhealthy, unbalanced diet possibly constipation.
Most doctors will tell you to aim (aiming is sometimes difficult to do) for Bristol 4, these are long, thin, soft as easy to pass. As an AF suffererer, these were making me retear over and over. Mine, although soft, were rather large, and this was due to the huge amount of fibre I was consuming. Lots of fibre = big poohs!
I've just had surgery 6 weeks ago and my first stool was a 4 but it hurt like hell. After a week or so of drinking plenty of fluid, overly chewing my food, eating only soluble fibre (google soluble vs insoluble fibre for the difference) and taking Movicol stool softeners 3 times a day, I managed to retain a Bristol 5-6 and I'm still going strong with them now.
If you're in pain whilst passing a stool, try to aim for a BS6 which should be like toothpaste.
You can do this by not eating junk food, eat wheatabix with plenty of fruit, try adding some flaxseed which will give you your fibre intake, prunes, mangos, all veg like broccoli cooked well. Avoid white bread and white rice. Avoid red meat as this doesn't digest easily.
Chew all your food well to make it easier for your tummy to digest it (if you leave big lumps of meat in there, it takes longer to break it all down). Chew chew chew.., and then chew it a bit more.
Drinking 3-5 litres a day, one litre with every meal.
Oh and no alcohol. It's tough but if you want to kick that nasty fissure, it's a small time to give it up for a joyful life.
Hope this helps, find a routine that works for you and stick to it, everyone's different - whatever helps you poop, use it to your advantage.
Take care of your diet and you'll be fine if you're in the early stages. Keep us informed and we're all happy to help with your routines further.
Welsh x