You might try introducing a second bucket to rinse the mitt before dipping again into the suds (both buckets can have suds).
You might try making sure you have a good amount of suds to provide lubricity during washing, so that you don't introduce micromarring during the washing process. In other words, add more car wash concentrate.
Also add a second mitt into the mix for the lower body panels and the wheels. It can be a different type so you know which is for which, and I usually use a microfiber for this purpose.
Add a product like our FX Spray Wax to the drying step, which should include only high-grade microfiber or 100% cotton terry towels. Spray wax will aid in drying, provide lubrication for the towel, and help provide gloss and protection.