Check the mash temperature and pH

We usually aim for a mash temp of 152°F for the Pale Ales we make.
It's a good idea to check your temperature in at least 3 places to insure an accurate reading.
A higher mash temperature will result in a sweeter, less fermentable wort.
Remember MALT = More Alcohol Lower Temperature

It's also a good idea to take a sample of the mash after about 10 minutes and check the pH level. Ideally you want it around 5.2 for proper conversion of the starches to sugars. We use a digital pH meter, around $50, but you can use the paper strips as well, just be sure to let the sample cool to room temperature before reading them. If the pH is to high you can add a few tablespoons of distilled white vinegar to lower it to the appropriate level. If it's too low, you can add a little chalk (calcium carbonate) to raise it. Be sure to mix any additives in thoroughly. The way we tend to do the pH adjustment is to add the vinegar to our strike water before doughing in to get a level of around 7.0 pH. This has resulted in an acceptable mash pH every time. I find it's easier to adjust the water then to have to screw around with the mash, it also mixes easier.

When I get the temperature I am aiming for, I cover the tun up with a thick blanket and let it sit for at least 60 minutes. For heavier, high gravity beers I will let it sit for 90 minutes.