Willing to forgive is the main part, but never let someone get away with a crime without rebuking them. You will create absolute monsters out of people by treating them with love after they've committed a wicked act. '...when the king does not exact justice right away, the people lose heart' (Prov).
Jesus spent half the Gospels rebuking the disciples, Paul rebuked Peter in public, and it goes without saying how ashamed that Peter felt. The Corinthians were told to ostracize the malefactor for a time, in order that he feel the shame of his ways. Paul exhorts to rebuke a sinner in public so that others may fear acting in the same way (1 Tim 5:20, Titus 1:13). It is extremely remedial when one feels the shame of a crime or sin. This is why God forbids certain things, because they are shameful. God rebukes the ones that he loves. It's the best thing that you can do for a troublemaker, is to rebuke him and expose the destructiveness of his act.
Christians need to be more austere, and stop the pseudo pious nonsense of just forgiving carte blanche. When appropriate and deserving, be confrontational the way that Jesus constantly was. Again, the transgressors greatest fear is that you expose him for the coward & louse that he is, and his greatest hope is that you forgive him without asking any questions.
Forgive, but do not overlook the crime, that's just naive and stupid. For, all you are doing is giving tacit approval to his offense, and giving him license to repeat it. Call a spade a spade, and treat them accordingly, you will be doing a service to all those affected by the offense, and the offender.
Salvation is contingent upon repentance, so should your forgiveness be, otherwise your perceived indifference will be misconstrued as approval. 'If they refuse to repent, wipe the dust off your feet in protest against them'.