How can the Danish Gambit be exploited? When dealing with gambits, especially ones where your opponent could have a lot more active pieces to pressure you. Is declining the best approach?

A friend of mine usually always wrecks me with the Danish Gambit, especially whenever I accept and before I know it, she's literally attacking  with way more pieces than I can handle and to be honest it does seem like a solid sacrifice (3 pawns for 2 very active pieces (the bishop pair) while  I literally have nothing to show for the first 3 moves).

Is there a solid way to exploit the fact that white is down 3 pawns? Or even better, what is the best approach to fighting back when the pressure is too much and I'm so behind in development?
The Danish gambit isn't very popular these days because of the Schlechter Defense. The idea is to take the gambit pawns but return them quickly.


  
  e4 e5 2. d4 exd4 3. c3 dxc3 4. Bc4 cxb2 5. Bxb2 d5
  


5...d5 initiates the Schlechter Defense. The mainline continues 6.Bxd5 (6.exd5 Nf6 closes the position and lets Black develop, still a pawn up) Nf6 7.Bxf7+ Kxf7 8.Qxd8 Bb4+ 9.Qd2 Bxd2+ 10.Nxd2 c5. Black regains the Queen and steers the game to an equal endgame. White has no attack and the position is not even remotely close to tactical, which is psychologically depressing for gambit players. 

[FEN ""]

1. e4 e5 2. d4 exd4 3. c3 dxc3 4. Bc4 cxb2 5. Bxb2 d5 6. Bxd5 (6. exd5? Nf6) Nf6 7. Bxf7+ Kxf7 8. Qxd8 Bb4+ 9. Qd2 Bxd2+ 10. Nxd2 c5


The only downside of this defense is, if you keep using it, your friend might not want to play with you anymore.