Rental acquisition with bad tenants

[Jennifer Fernéz]

Im looking at properties to buy, and saw a tenant in a 4-unit property I like paid $1,000 in late fees. They are also smokers and their unit is horrid. They are month to month. What are common practices to remove them? Another tenant in the same property pays $750 a month and should be paying more around $1100. What is the best way to increase her rent?   Do I do it all at once?  I need help with etiquette and what to do