KristinHolly Wrote:The more effort you put into this job, the more results you see, so it's rewarding.
I think this gets the idea of the sentence across and is a natural translation but I'd like to add my thoughts, which I hope help. From the point of view of producing Japanese (rather than understanding it), I would translate "The more effort you put into this job, the more results you see" as
「この仕事は努力すればするほど、成果が現れる」
Or more generally, "the more..., the more...." is translated as 「・・すればするほど・・」.
In this case, だけ can be replaced with 分(ぶん) and the sentence retains the same meaning. だけ generally acts as a limiter for whatever proceeds it. In my mind, I view it as a word which draws a boundary around something and says "as much as this, but no more". So the idea here is that if you put in an amount of effort, results will appear for that amount. KristinHolly's translation implies proportionality between effort and results, which is implicit but not explicitly stated. Not really a big deal though.
It's also worth pointing out that the second sentence is conversational and the first sentence isn't.
Also, if you're looking to pass the JLPT, I don't think that translating everything is a great idea. It's better to understand the sentence rather than be able to produce a close equivalent in English.