Up and Down stroking

[Emmiemando]

I've been taking mando lessons this past Spring and learned many things. My teacher has been gone for the summer and isn't coming back until late September. He gave me many-many things to practice. He said to work on my downstrokes in playing a song (basically only stroking down). But some songs are easier to play doing up and down strokes. My tone sounds great when I'm down-stroking, but when I do the up/down, I lose it!
Anyone know any good practicing solutions while the teach is gone???
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[steve in tampa]

Lighten up on the strings slightly on the upstroke. Push back down on the downstroke. Both hands have to simultaneously do the work.