I think that to an extent you make your own luck. If you do the groundwork/preparation/research, then when an opportunity does arise you are more likely to recognise it as an opportunity and are more likely to be prepared to exploit it. The second component of this type of luckiness is possessing the courage to take the opportunity presented.

I don't believe in manifesting as such but I do think making your own luck is related to it and might even be an alternative term for the same thing.