The deeper you bend your knees--and the lower you get your butt--with each stroke before pushing off for the next one, the more you will need to push off and extend the leg you just pushed off from. So focus on keeping a wide stance, with deeply bent knees and butt low to the ice as you stroke. Push off from left to right and then from right to left, rather than thinking about going straight forward. This will make it more natural to extend the leg you're pushing off from (and point the toes!). Since you are pushing off from side to side, there should be no toepick pushing. It should all be from the edge of the blade. And that means your push-off leg will extend somewhat to the side (7:00 or 8:00 for the left leg, 4:00 or 5:00 for the right leg). Just remember, the deeper you bend before each push, the more time you have to fully extend the free leg.