The single biggest factor in learner success is a learners ability to self-regulate their learning. It is the exact opposite to 'learned helplessness' that you should read about here. Learn about it, understand it, and you will become a better educator.
Of course, self-regulated learning (SRL) is not easy to develop in learners particularly learners who have been beaten around by the educational sector. Also SRL can be broken down into many sub-skills and dispositions that are generally developed separately but used cohesively.
I used to think that SRL was the secret to developing the potential of adult learners with problematic learning histories. I used to think it was the answer to the literacy and numeracy problem. No more embedded ELN, no more literacy or numeracy provision - just SRL.
I now realise that sitting below SRL are belief systems that dictate SRL - beliefs are the mainspring of downstream effects.