There is no "right" or "wrong" way to improve ad starts, however below are a couple of guidelines that may be beneficial to help optimize:
It's important work with vendors who can provide you the fill rate that you need. Often times Networks will reduce or stop sending traffic to tags.
Tag Performance + Speaking with Vendor
Another good practice is to check on your tag's performance levels and speak with your ad vendor when you see your metrics falling. You can check the tag's metric performance Player Ad Timings report.
The tag itself is important but where it ends up being called plays an equal, if not greater, role. Players that wind up on publishers with high traffic such as unique visitors, page visits, and page views will yield greater ad opportunities.
Note: Some publishers increase the number of ad opportunities by showcasing multiple players and/or network campaigns onto one page causing a huge lag and user experience. These type of sites will end up costing you to host your player than you would receive in ad opportunities. It is highly recommended that the site quality is checked beforehand.