As I see it, the main aim of any team selections in Preseason is to score the most points possible for the lowest price possible (let's call this concept value). Therefore, I think in positions where there is lots of value available it's important to take it, and then focus your early gun choices in positions where there isn't much value.
Cam Smith is undeniably the best scorer (and therefore captaincy choice) in NRL fantasy. But for almost $1M, he'll chew up roughly 1/10th of your cap for literally 0 value. For that money you could almost get Cook AND Licha. Personally, I'd rather get them and then pick up Fifita, since I think there is much less value available in the FRFs.
Last year I started Macca and Brailey. Definitely a bit lucky, since I expected Macca to be value but didn't expect him to match Smith's scoring over the first 12 rds. Over Origin I moved to Friend and McInnes, who I finished the year with. I had intended to bring in Smith for the backend of the year, but a few wasted trades early prevented me from doing that.