All of my accounts are either $1k/day or over the $1k limit except for my most recent one. But that doesn't seem to have anything to do with getting an ad auto-approved because its limit is $250/day and I rarely see an ad that gets disapproved. All I do is if it does get disapproved I change the title and text by one or two words, pause the campagin itself, resubmit, and poof, it just works. Maybe the pausing it has something to do with it, but thats the only thing I can really think of.
Also I tend to start off bidding kinda high to get my ctr up. As soon as my ctr hits the .10% mark I lower the bid a lot to something I'm more comfortable paying to still get at least a 3:1 ratio of my ROI. I see a lot of you talking about much lower CTR's, and I think you need to play around with the bid pricing more from the start, rather than from tweaking nonstop. Once you hit your desired CTR, then just lower the bid price, and leave it alone to do its job and just go on to the next campaign.