Rob Cassam I'll drop this little tidbit here from the course since it seems relevant to what you're asking.
Depending on what I determine a property's market value to be, I'll adjust my offers up or down as a percentage of what I think it's worth.
As this sliding scale implies, I'm willing to offer a higher percentage of market value as the market value increases. If the seller appears to be highly motivated or apathetic about their property, then my offer will be on the lower end of the range I've set for myself. If I think they'll need a higher offer, then I'll lean towards the higher end (but I rarely exceed it).
Now, keep in mind, I'm more on the conservative side of most land investors I know. I know plenty of people in more competitive markets who will offer upwards of 40% - 50% on some properties, but that's not something I'm willing to do unless it's a unique situation and I'm VERY confident about it's value and that the property will sell quickly.
This offer-to-value range isn't a set of rules you need to live by (feel free to create something similar for yourself with different numbers based on the market where you're working... if it's a high-demand market where properties sell quickly, it could easily make sense to offer more).
Nevertheless, the idea is, if I ever have any doubt about what my offer price should be, this gives me some clear instructions on what to do (and I keep my number on the lower end of the spectrum if I'm not very confident about the property's value).
In some markets with more competition or a higher demand for vacant land, it may make sense to go higher (or maybe even lower) than what this scale suggests.