If you're confusing the difference in listening and speaking "things/thinks", then you must learn the "ng" sound properly.
"Things" ends in a hum at the back of your throat, before the s (the s also is sounded as z).
"Thinks" ends plosively, with a hard k before the s. (The n is actually also an ng sound. Easier that way.)
The difference is huge to an English listener, but I do understand how this misunderstanding happens.