What sorts of things make a person more likely to get sepsis?

Immune compromised. This is a big question in critical care medicine: why do some people develop sepsis or multiple organ failure and others not? Known factors include age (the very old and young), immune compromise (from lupus to pregnancy to diabetes to leukemia patients), the virulence of the pathogen to obvious factors like abdominal injury with spillage of fecal material, etc.
Diet, . A diet high in omega 6 fatty acids predisposes to sepsis. Chronic diseases where bacteria can invade normal tissues such as COPD and inflammatory bowel disease can lead to sepsis. Anything that weakens the immune system can lead to sepsis.