If you are rubbing the stains in your clothes very hard, you have to stop because you are just making it worst plus you are just wearing away the fabric of your cloth. Just be gentle and take time, do not rub but dab.
If you are using too much detergent, you have to stop because excess of froth or synthetic detergent compound can hold dirt in the clothes instead of fading it away. This could also leads bacteria to build up especially in the collar part. The solution for this is just use enough amount of detergent then just add up detergent when you notice that the clothes were not clean enough for the amount of detergent that you used.
Usually we fill our washing machine first with water, then soap and last are clothes. This is wrong, although this protocol was right from before to prevent residue but with modern detergents this is no longer correct. Modern detergents are already phosphate-free and are not harmful to clothes at all. So the correct way to fill our washing machine now is first fill it with clothes, then water and then soap however this process is when you are not using bleach.