As soon as a tenant problem is brought to the attention of the landlord, they need to be made accountable.  By holding the tenant accountable for their actions, you decrease the chance of them becoming a problem tenant.  In doing so, you must inform your tenant when their conduct is inapporpriate be it financial or social. 

Put them on notice!  What do you do to stop them from victimizing other tenants and the next landlord?

• Notify them when their conduct is unacceptable;
• Don't just set rules when they move in, remind them frequently;
• At the first sign of them breaking their lease, serve notice;
• Make sure the consequences are clear;
• Get judgements against them if they owe you money and damage your property;
• Try to collect what they owe after they move;

If you are consistent with your tenants and hold them accountable by following through on what you say you are going to do, you will have far less problems, and you will have more cooperative tenants.