What is Practice actually supposed to do?

[Jalepenito]

Lately I've started my time on Duolingo by practicing. I figure it's a good warm-up before a lesson. I also thought I'd get questions that would strengthen my weak areas. For 4 days in a row now I've had a weak area. Today I had 2. I needed to practice twice for the new weak area to strengthen. But the weak area I've had for 4 days has yet to be strengthened. Isn't Duolingo meant to rotate words thru regularly to keep them in our memory? Isn't practice the perfect time for that? Is practicing enough or do I need to click on weak areas manually?

[ZaheerA.]

I have found that a combination of practicing, going through flash cards and doing new lessons can make all the weak areas go away in a day or 2. Although they return quickly if I skip my practice streak the next day. The only solution is to try your best to maintain your streak.

[Jalepenito]

I could do flash cards more often. That's a good idea.
So practice is supposed to strengthen weak areas. I'm only down one bar and 4 days with 5 or more practice sessions hasn't changed anything. I guess it's a glitch.