I think one shouldn't care about the questions vs. answers rate. I'd much rather have people asking only questions - but good ones - than people feeling compelled to give back, even though they may not be able to provide quality input yet.
As to voting... Hardly any of your peers will care about your voting ratio, except in extreme cases where downvoting outweighs upvoting massively. In those cases, your voting privileges may get limited.
The problem with this is that heavy downvoting can have two reasons: 1. you scrutinize the content provided on SO, and downvote where it fails your high professional standards; or 2. you are an asshole. The same goes for upvoting: One can be either very engaged and simply giving a lot of positive feedback, or a mindless nice guy upvoting out of sympathy rather than based on sound judgement of the answers provided.
Which is which is hard to tell, which is why I'd say this is down to your own judgement. I myself, for example, with a ratio of 3800 upvotes to 225 downvotes, feel I could do some more downvoting... but it's not really important.