Always worth repeating...

• Everything Erg - links to technique videos and Workouts of the Day - https://www.concept2.com/indoor-rowers/training

The following workouts assume no timekeeping gadgets other than a watch.  Any time based workouts can be modified for stroke-counting. 

• Pyramid Workouts
  • Do 10 strokes as hard as you can, followed by 10 easy, then 20 hard, 10 easy, 30 hard, 10 easy, 40 hard, 20 easy, 50 hard, 20 easy, 40 hard, 20 easy, 30 hard, 10 easy, 20 hard, 10 easy, 10 hard. You could also make all the easy intervals the same number as the hard intervals for easier memorizing.
  • 20 strokes easy, 20 strokes hard effort, stroke rate as low as you can, 10 strokes hard effort, high stroke rate, increasing the stroke rate each stroke over the 10 strokes. Repeat for a minimum of 15 times.
  • 10 min of earnest steady state effort (you're trying but could hold a conversation), then 7 min of 80% effort, then 3 min sprint. Rest for 5 min, do again. 
• Time-based workouts
  • If you have a watch, fasten it on your rigger or oar shaft so you can see it (but of course, don't focus so hard on your watch that you forget to look behind you!). Otherwise, count strokes.
  • 30 sec on, 30 sec off until failure (probably 15-16 strokes on if you're working hard)
  • Row 45 sec as hard as you can, 15 sec rest, ten times (23 strokes hard, 7 strokes easy). Paddle for a few minutes so you can catch your breath, then do another set of ten. 
  • 5 min (or 100 strokes) of low rate, high power rowing. Keep the recovery as slow as possible. Take 2 min rest in between, and do as many 5 min intervals as you can. 
•  Distance intervals
  • Map out lengths for your pieces.
  • Break up the piece into thirds and row the first third hard, the second third easy, then finish hard for the final third. 
  • Start out steady state for the first third, then 75% pressure for the second third, then 90% for the final third.
• Drills
  • Take three strokes and pause at body over (10x), three strokes and pause at quarter slide (10x), three strokes and pause at half slide (10x), three strokes and pause at 3/4 slide (10x). When you're finished the pauses, do a few power 10s and see if you feel a difference in how the boat moves. 
  • Everybody's favorite: pic drill! 10 strokes arms only, 10 arms and body, 10 1/4 slide, 10 1/2 slide, 10 3/4 slide, 10 full slide. You can also do reverse pic drill where you start with legs only, do legs and back, then legs back and arms. 
  • Row2k publishes "Technique Features" which are short articles that contain great information on different technical aspects of rowing. They typically include helpful pictures, drills, and explanations for both coaches and rowers. 
• Just for fun
  • Try a racing start sequence! Sit at the catch at 3/4 slide with your blades buried. Then, as fast as you can get the oars moving, do one 3/4 slide stroke, one half slide stroke, one 3/4 slide stroke, one "lengthen" stroke between 3/4 and full slide, and then a full stroke. Continue as fast as you can for ten strokes. 
  • Leap frog: Row with a friend. One of you will row at normal steady state, adding a pause if necessary to keep things even, and the other will pass while sprinting. Once the "passer" has finished passing, alert the other person who then becomes the "passer."