Well, first of all you can use a tool like Buffer to gauge the strength of your following. I'll paste an example below.
- Screen Shot 2014-05-29 at 11.42.07 AM.png (26.97 KiB) Viewed 1343 times
- Screen Shot 2014-05-29 at 11.41.06 AM.png (29.26 KiB) Viewed 1343 times
These are stats from two of the tweets that went out on @kickstartforum via buffer.
The first one got 7 clicks, 3 retweets, one favorite, and an overall potential audience of 17.3k (because of the retweets).
This is a click through conversion of about 0.04% for that one tweet (out of 17.3k).
The second got 11 clicks, 1 mention, 5 favorites, and 2 retweets for a potential audience of 9.6k audience (retweets enhanced the audience).
This is a click through conversion of about 0.11%, almost 3 times that of the previous tweet. The reason it's three times as high is because it's out of a smaller audience (9.6k).
You can use wording and time (note the time on the tweets) to trial and error test which types of messages resonate with your followers and either yield greater retweets or clicks.
I personally find that experimenting with headline writing for links that have been written about your campaign gets more engagement, but ALWAYS follow the analytics, not necessarily my or someone else's advice. Campaigns vary. The only way to really figure out what types of messages yield greater conversions is to experiment and track those experiments with analytics via Buffer or Hootsuite (I prefer buffer).