There are cases described in the A Song of Ice and Fire books in which some commoner gains a title of knight/lord, knights gain a title of lord, and lords gain more influence and land - the individual climbs up the feudal ladder. I know that battles are among such cases.
The most notable example is the Battle of the Blackwater where several honors have been given out after the successful defense of King's Landing.
The first part of the my question is: Apart from battles, what other cases of granting honors and land are described in the books?
For the second part, I am wondering if a knight/lord has some initiative to get a title or land. I mean something like
Petyr Baelish's conspiracy which turned him from a meaningless, poor, virtually landless lord to high lord of Riverlands.
but on a smaller scale.
Can some petty lord raid and take over some other lord's land (excluding actual war)? What would be the higher lord's reaction? Can a high lord take land from one of his vassals and grant it to the other, or is only the king able to do it?
To sum it up: What can a knight/petty lord do to impove his situation in the feudal hierarchy?