Off the top of my head I'd say there are at least three ways to evaluate your technique:
1) Use the "Force Curve" display on the PM (assuming your erg has a PM3 or newer monitor) to assess your overall stroke. See the C2 link below for more information.
https://www.concept2.com/indoor-rowers/ ... orce-curve
2) Take a video of yourself from the side and compare it to the C2 videos at the link below. This is actually a bit tricky, because for new folks it can be hard to notice all the details that can potentially throw off your technique. However, you should be able to catch the really bad stuff. C2 also has several "Common Errors" videos that might help.
https://www.concept2.com/indoor-rowers/ ... ng-started
3) Save your video someplace online, and start a thread on the "Training" sub-forum with a link to your video and ask folks what they think. Many here are super-knowledgeable and happy to help.
And finally, I hesitate to do this, because it perpetuates the myth that "if you're going fast you must be rowing properly, and if you're going slower than XYZ standard you probably aren't" but I'll say it just the same:
Based on your average pace in say, a 2k or 5k steady-state workout you'll get an idea of how well you're doing. As a newcomer if you're already down in the 2:00-2:20 pace range with a stroke rate around 20 strokes per minute then you'll know that you're doing quite well and probably have decent technique. (congratulations) But if you find yourself stuck around 2:30 and up, and have to use a very high stroke rate of say, 28 spm or higher to get there, then you may well have issues that need to be addressed before moving on to more serious training. (I see plenty of those on the Model E at my gym)
Feel free to ask any questions you may have - folks here will be glad to assist.
Good Luck
