[JPablo]

I'd just say,
some do all the work and others get all the credit
Some people do all the work, and others take all the credit

I also heard it like this,
unos cardan la lana y otros cobran la fama
uno siembra, y otro recoge.

In Catalonian you have, Uns alcen la caça i altres la maten
[There are the guys go get game in the out and there are other ones who kill it]

One man sows and the other reaps.
Some sows, other mows.
Some do the sowing, others the reaping.

Then, something a bit different, (I think the above answers your question already)
Something like "to set a herring to catch a whale"
Who ever caught anything with a naked hook?
Venture a small fish and catch a big one...