Tips on The Greek Gift I always have problems in  executing  The Greek Gift. This a position which I got in a recent game :

rn1q1rk1/1b1nbppp/p3p3/1p2P3/3N4/2NB4/PPP1Q1PP/R1B2RK1 w - - 3 13


Even though the Knight is not there on f6 square and can't come here safely, I lost after scarifying the Bishop.

Can someone explain when and when not to use the The Greek Gift and give some tips regarding the same?
The main tips are:

1) A pawn on e5 helps. Not only does it prevent ...Nf6, but it also takes away the f6-square from Black's king once it comes to g6 (via ...Kxh7-...Kg6).

2) The greek gift is usually followed up with Ng5+. So if the g5-square is defended by Black, or if you don't have a knight on f3, this idea won't work. In some cases perhaps you could make do without the knight, such as Qh5+ followed by bringing a rook to the h-file, but in the position you posted that doesn't look feasible. Rf3 is prevented by the b7-bishop, while Rf4-Rh4 runs into ...Bxh4.

3) Assuming that a Ng5 follow up is possible, calculate the position after: Bxh7+ Kxh7 Ng5+ Kg6. This is usually what happens in the greek gift, since Kg8 runs into Qh5 (with Qh7# threatened). In the position after ...Kg6, how will you follow up? If you play Qg4, can ...f5 be met well (perhaps with exf6 or Qg3)?

4) Make sure that if Black answers Ng5+ with Kg8, Qh5 would truly be winning. For example, can the king escape in any way, or can the h7-square be guarded?

5) Do a force count of the kingside - who has a stronger armada of pieces concentrated there? For example, in your diagram the f1-rook is opened on the f-file and can be a great contributor. But again, since there is no Ng5+ follow up, the idea doesn't work.