Traffic vs Conversions is not the first question...its Income or Cost
Often you need to step back and remember that IM is not a game, is not a sport, is not a hobby (well it sort of is all 3 to some people) but really it is first and foremost a business.
In a business, when you decide to make change. You start at the meta focus, above the process. Everyone here's focusing on traffic and conversions, yada yada yada.
Your first decision should be whether to focus on Cost or Income. If you want to increase your ROI, the fastest way is actually to decrease your costs.
These could be by reducing your personal time investment. Could be by cutting back needless costs (like not buying 90% of the get rich quick guides). Reduce your server costs, I would wager you aren't using 10% of the server power you thought you were going to need when you started this IM thing of yours. Or hey, the world is flat, Outsource Outsource Outsource. Freelancer.com is a great service.
Yes obviously increasing traffic and conversions are great. However if you want to make a fast and positive impact to your ROI, take a lesson from corporate America, cut costs first. Then you can more profitably focus on increasing your Income via traffic or conversion rate improvement.
nothing to see here.