Help With Mirroring Ford GT

I’m working on modeling a ford gt, and was wondering how to mirror it so that as i was building it, it was mirrored so i would only have to model one side.
Thanks guys!

add a mirrior modifier and set the x coordinet,
that ought to do ya,
you might need to select all the verts in edit mode and move them right or left in front view to see the resulst, and turn do clipping on
hope this helps

What i do to MAKE 100% sure the verts snap perfectly is:
(Mirror Modifier Must be on and above the Subsurf modifier & you must have it enabled in edit mode.)
(Subsurf = On {You will see why if you try it… you can undo it later})
(Select central Vert {Mirroring vert})
(G+X move them until the color of the subsurfed faces snap.)
(Note: I told you to subsurf them because its easier to tell if they are perfectly snapped because when subsurfed the faces will NOT make a combined face unless the thwo verts are 100% and totally snapped this is a good way to know if they are snapping right, once done doing the snapping {once your 100% sure you have no more changes to do} Apply The modifyer and now The object is not just a reflection but just 1 big one.)