Depends on your Machine:
If you use a top-loading washer, then you'll need a warm pre-wash phase with some detergent and soak for a while before draining, spinning and adding more detergent for a HOT wash (longest time) and high-speed agitation. Use a good quality POWDER detergent... Powder cleans the best and is quite cheap in bulk sizes.
For an FL machine, depending on the style of machine (US or EU), you need to set the machine for a "Hot" wash with Pre-Wash (Tub will be cool, so you'll get a "warm" wash).
Then, on EU machines, select a Boil or anything north of 140° for the main-washing period, extra rinses etc to really rinse your detergent out, since you WILL have significant loading for this cycle.
For US FL machines, Hot wash on a "Whitest Whites," "Steam," or "Sanitize" cycle (or you can use modifiers on a default cycle if you have them). If the machine has an extra rinse option, USE IT. If the machine lacks a water heater, manually do a Pre-Wash in Warm-Hot water, cancel the cycle and reset for a full HOT wash. Purge the closest hot tap to ensure best results.
On ANY machine, unless you want to waste additional time rinsing clothes between the washes, DON'T use lots of detergent for Pre-Wash. Only about 1/4 or less of your regular dosage, since you are soaking or only gently agitating for a little time. Save the detergent plus oxygen bleach/bleach for the main-wash phase (The latter can be added at the END of the wash to save enzymes). Keep the dosage high for the soil level and remember your extra rinses so that you don't get a rash from detergent.
