So I am thinking about getting a used 2008 Lancer GTS for my first car, but I've heard issues over reliability. Could anyone post what they've had, and possible ways to prevent it?

if there having issues after 1 year... thats really sad

Make: MITSUBISHI Model: LANCER
Model Year: 2008
Manufacturer: MITSUBISHI MOTORS NORTH AMERICA, INC. Mfr's Report Date: MAR 05, 2009
NHTSA CAMPAIGN ID Number: 09V077000 NHTSA Action Number: N/A
Component: SERVICE BRAKES, AIR:SUPPLY:CHECK VALVE
Potential Number of Units Affected: 39711
Summary:
MITSUBISHI IS RECALLING 39,711 MY 2008-2009 OUTLANDER AND LACER VEHICLES. INCORRECT MATERIAL COMPOSITION OF THE BRAKE BOOSTER CHECK VALVE MAY CAUSE THE CHECK VALVE TO STICK CLOSED WHEN THE ENGINE IS SHUT OFF. WHEN THE VEHICLE IS RE-STARTED AND PUT INTO MOTION, UNDER CERTAIN DRIVING CONDITIONS (VERY SLOW VEHICLE MANEUVERS), THERE MAY BE INSUFFICIENT INITIAL BRAKING ASSIST.
Consequence:
THIS MAY TEMPORARILY INCREASE THE STOPPING DISTANCE OF THE VEHICLE AND THEREFORE INCREASE THE RISK OF A CRASH.
Remedy:
DEALERS WILL REPLACE THE BRAKE BOOSTER CHECK VALVE FREE OF CHARGE. THE RECALL IS EXPECTED TO BEGIN DURING APRIL 2009. OWNERS MAY CONTACT MITSUBISHI AT 1-800-222-0037.

aside from that, i'm not aware of any glaring issues. be sure the car is still under warranty.

if there having issues after 1 year... thats really sad

some mitsubishis aren't exactly the most reliable cars out there