How to do laundry….?

Long story short: I was never shown how to properly do laundry.

I separate the whites from the rest of the stuff. Start the wash with cold water (I always use cold water) through in some Gain Apple Mango Tango detergent (because I love the smell) put some of the same brand fabric softner into the little thing on the top where its supposed to go and thats about it. When the washer is done I throw it all (unless there is something delicate) into the drywer with a dryersheet of the same brand.

I feel like I am missing something and my whites never stay white! (When its a load of whites I also put bleach in)

Do you have any tips or great suggestions??? What can I do to make my towels/sheeets smell better longer?

Thanks!