Laundry 101

Just curious everyone's frugal tips for doing laundry. Have heard conflicting thing such as use good detergent (Tide generally) vs generic cheap stuff. Add vinegar or baking soda. Pour in detergent right away, let fill up than add clothes vs start with clothes. Cold water vs hot.

I have tried a few of these but haven't noticed much difference. Tried doing cold with Tide cold detergent but seems like it never soaps/bubbles up? Open to anything!