There are two ways to decline the gambit:-
(A) Bc5 variation.
(A) d5 variation- This variation is also called Falkbeer Counter Gambit
Note:- Although White has centre, Black has strong pawn on f4 which is well defended and there is equal opportunities for both sides.
Game-1: look at a beautiful game below
Game-2: look at a beautiful game between Spassky and Vasilievich