I use the Twitter search function. You can do this with 10 followers and still make money.
Ok, let's say you are promoting a product like a free Wii. You go to the Twitter search and do target searches for keywords that would relate.
For example, people looking for a free Wii are obviously into gaming, right?
So you would go to Twitter search and punch in searches like "video games", "gaming", "wii", "new game", etc.
It will return results of all tweets that have those keywords mentioned.
Then you just reply to those people with something like: "Hey, I see you like such & such. I just got a free Wii here", or something like that.
Not only can they see it, so can all of their followers, who are probably interested as well because they follow like minded people.
When you search, put the keyword term in quotes and then a trick is to put -http right after it. This will take away most of the Tweets with links in them. The reason for this is that most Tweets with links are other marketers and there is no sense targeting them.
If you have time, you can do this all day and make money.
Just don't tweet the same thing. You have to change up the tweets or you'll get flagged.
Better yet, you could hire a VA to do this for you. In fact, there was a video course a while back that talked about doing this with Clickbank and gettng a VA from the Philippines for $15 a day.
The reason why the OP's method didn't work that well is because it's probably not targeted towards people who actually might have been interested.
However, offering a freebie woulf work well. You got 600+ clicks. I wouldn't even send them to a squeeze page. I'd create a free report or use PLR and put a link inside to my squeeze page or affiliate links and then just send the Twitter traffic to a page to download the report for free. Just about everyone would probably download it.