what makes a rubbish sub?

[Pearlgem]

A sister thread to the one about arsehole Doms.

While a great many useful observations are being made about Doms who don't cut it, one thing that comes up time and again is that often subs 'ask for' the mistreatment they receive (not in a good way) because they are insufficiently careful, smart or restrained about linking up with a new Dom. They invest far too much of themselves far too quickly without really knowing (or caring that they don't know much about) the person they want to devote their submission to.

So my questions are these:

How can a sub help herself out of that spiral of disappointment with Doms when actually it's largely of her own making?

How do you spot a wannabe sub?

Especially for the Doms, what early signs warn you not to risk further involvement, or is a sub at your feet irresistible no matter the circumstances?

I'm presuming we'd be talking about on line, early stage relationships.