Personal craft could mean escape pods, shuttles, fighters, etc. An example would be the DSTT-1, a modified escape pod used by shock troopers to quickly reach planet surfaces. Or, the Empire's acclaimed Twin Ion Engine Fighter, a fearsome ship-to-ship fighter designed to fly fast and fight hard.
Frigates are the simplist military ship a navy can have. They generally fly at a near-atmospheric orbit, and have the capability to land on a planet. Most are lightly armed, and are primarily used for troop transport or scouting/patroling. They are almost never used for head-on engagements, unless there is no other option.
Cruisers are much larger than Frigates, and usually engage in ship-to-ship combat. They are usually quite large, and have a massive array of weapons to use. Cruisers can be used for planetary bombardment, fleet engagements, troop movements, and other uses.