From my own beginning breadmaking experiences years ago to those of the people that I've helped make bread over the years, one thing stood out more than any other when it came to problems. That was the yeast. The temperature of the liquids had to be just right. Too hot and you killed the yeast. Too cool and the yeast didn't activate. Or sometimes the yeast just wasn't good to begin with. All that work and all of those wasted ingredients made for some disappointment and frustration! (And lack of bread! :-[ ) After working with that type of yeast for years I was very happy to learn of a better yeast that didn't have such a temperament. SAF yeast (and another one that the name of escapes me right now) is a professional baking yeast that is so easy to use. This yeast will rise even of you use cool liquids. Of course, it will rise faster if the liquid is warm, but you don't have to worry about it. The dough rises a lot faster, too, because there are a lot more of the yeast cells. This is an instant yeast so it doesn't need proofing. You just stir it into your flour and then add the liquid.
Years ago this yeast was only sold in a few places but now it is easily found. ( I was going to put a picture of it here but for some reason it isn't working.) It is reasonably priced and will last a while.
When a recipe calls for a package of yeast I use one tablespoon of SAF yeast.
Psalm 104:15 "........and bread which strengtheneth man's heart."