Draw the mechanism for the reaction of an acid chloride with an alcohol to form an ester

First thing to remember is that when drawing curly arrows, the arrows start where the electrons start and finish where the electrons end up. For this reaction the lone pair of electrons on the oxygen from the alcohol attacks the carbon of the carbonyl group and an electron pair from the C=O bond gets pushed up onto the oxygen. This format an intermediate. The alcohol group is now positive so looses an H⁺, the chlorine is kicked out becoming Cl^_ and the double bond (C=O) reforms. (mechanism would be drawn on whiteboard)