Not many pieces are left. White is up a pawn. It looks like a drawish position, but it's black's turn.
First candidates come to my mind are Qd6+ or Qd4+ check. We wish we can skewer white's Queen, but it's just our wish. White can easily block with its Bishop. We can't make any progress with these two moves, but we notice that after check, white King can't move to a5. That's a dead corner. Bc3#. OK, this hint gives us third candidate move, Qa5+.
Before we move on to calculate, let's pause and think why Ka5 is not good for white. All white Bishop, Pawn, and Queen are in light squares. They can't move over to block the Bc3# (Queen can move onto the diagonal but one square too far). I call this c3-a5 the blind diagonal for white, because white has no control at all, though he has many pieces nearby.
Back to our candidate move Qa5+. We know we are safe because of potential checkmate. Remember, wishing Kxa5 is just beginners' wish. Even if it's not solution, it's not bad to consider. First thought when I check this move is that we are releasing more control on the white King, because our Queen is in a man-made corner now and white King has c-h files to roam. We can check on c3. White King will go to d-file. Will this help? Yes, in fact, after Qe5+, we can drive the King backward to c4. It's amazing that our total control of dark squares can completely control white King and lead to mate in two more moves.