I don't have the money to wash in hot water (water heater went out, no money to fix it yet). I have found a few things that work, though. I can only use 3 brands of detergent because of itching problems. Tide seems to work a little better than All or Arm & Hammer, but it is not worth the increase in price.
First, pretreat any stains. This really helps.
Add bleach to whites - use off brands, it has the same stuff. Sometimes, I will use Iron-out because of my hard water or they sell a little package of whitener that seems to help. Don't do the iron out or the whitener very often, its expensive and not needed.
For colors, including towels, I use a color safe bleach by Purex. (not the same as borax - borax makes me itch). This product is one of the cheaper ones. It runs about $2 a box here and I don't have to use that much. I put it in the cold water before any clothes and swish my hand in the water to dissolve. It may be a little different with a high efficiency model though. This product works well and will brighten the colors (especially light ones) well.