Keep a bottle of your favorite dish washing liquid handy to pre-treat food stains. Just dab a bit on and toss it in the washer. I prefer brands that do not contain phosphates.
Mildew stains can be removed by making a paste of salt and lemon juice, then rubbing the paste on the problem spot. Dry the clothes in sunlight. Repeat as needed.
To treat ring around the collar, make a paste using vinegar and baking soda. Apply it to the collar and wash as usual.
Always leave the washer door open when not in use.
To remove the brown residue from your cold iron bottom, wipe it with a rag soaked in full strength white vinegar.
Hydrogen peroxide is amazing at removing blood from fabrics. Spot test on dark or high maintenance fabrics. I just pour it on the spot and wash immediately.