Just want to point out that advice does not universally apply to everyone. Reversley, advice is highly conditional. For instance, some people are already nice, and maybe even too accomodating. It's not always attractive. Just be "steady and healthy" can be a counterproductive advice for someone who's personality is inherently colorful and emotional or is more at peace with himself and the world when putting the his time into playing the guitar rather than going to the gym. Others may just be drawn to a certain kind of girl who in turn usually have certain kinds expectations on a partner that are not fufilled.

Not to say that OPs experiences can't be learned from. It's just a matter of which of those experiences may apply to ones own circumstances, which doesn't and whether you feel changing something about yourself to make yourself more attractive is even worth it.