How do you make cotton dish cloths absorbent ?

Don't use fabric softener.

First it depends on the quality of the dishcloth to begin with. Second, add vinegar to the wash, third, do not use fabric softener. Check these links out!

http://www.dishydesigns.co.za/how-to-make-your-dish-cloths-more-absorbent/

https://m.wikihow.com/Make-New-Towels-More-Absorbent

Make them out of an absorbent fabric like Terrycloth. Many people make them out of towels they no longer need.

Wash them first....

I found out a long time ago.... that fabric softener prevents fabrics from absorbing the way they should.... especially towels...

I always do an extra rinse when I wash towels (bath or kitchen) and I put vinegar in the fabric softener dispenser in the washer... I do not use fabric softener sheets in the dryer either.... it is the tumbling and heat that makes the towels not stiff... the dryer sheets just combat static.

FYI in the summer I hang dry heavy clothes like jeans and t-shirts and then just run the "touch up cycle" to make them soft.

Take them back to where you purchased them and say " they are not fit for purpose"