* you cannot apply to any Secret / Top Secret jobs until you have US Citizenship. Depending on the hiring agency they may choose to sponsor your investigation, but dont count on it. Your likelihood of being hired and sponsored for clearance is greater if you bring good skills to the table.
* Regular trips to Korea is not helpful for clearance purposes. Regular trips to China is definitely a bad thing.
* if you have bad credit or a lot of debt it is not good.
* arrest records/DUI, DWI, domestic abuse etc… really not good.. history of drug use, chances are zero