I also find that good old fashioned courtesy pays dividends, as does ensuring you put your customer ID in the email. ;-)
Syzygy
* Time-to-review can vary (and even vary substantially) with the number of ads being submitted. Sometimes this is beyond an advertiser's control - but other times it is very predictable. For example, it only makes sense that there will be more new and/or edited ads submitted in the weeks leading up to major 'retail intensive' holidays.
* Since ads are reviewed on a limited basis over the weekend, submitting new and/or edited ads late on a Friday afternoon may add a couple of days to to one's review time.
* Monday is a peak day for ad approval - so consider submitting your ads mid-week if you have the luxury of being able to do so.
* If you do decide to email about your ad approval, please take Syzygy's excellent advice and include information that will identify the account. You might be surprised at the number of emails we receive which are not written from the email associated with the account, and which do not otherwise identify the account in any way. This tends to slow response time. ;)
* For any email contact, I'd go even farther than Syzygy, and advise that you also include not only the account ID, but the names of the Campaign(s) and ad group(s) with which you are concerned. As someone who has answered thousands of emails over the years, I can assure you that this is very much appreciated - and saves quite a bit of detective work.
AWA