I also had this problem after I switched to continental style. But
this video by Cat Bordhi really helped me a lot. She's so comprehensive in her deconstruction of exactly why the tension is off and how you can fix it. The technique she is using is called Norwegian purl by some people.
This is a video that demonstrates very clearly how to do this by someone who was taught by a Danish knitter. That's the video that finally helped me nail it, but I still think the Cat Bordhi is necessary to watch first because of her great explanation.
Also, Norwegian purl has the added benefit of greatly speeding up your ribbing and anything like seed stitch that requires a lot of switching between knit and purl because you keep the yarn at the back of the needle for both! It's very efficient in those cases.
Here is a small seed stitch project you could try in order to test it out. Happy knitting!
