for the second part of ochem just memorize all the reactions, actually if you know the trend, most of the second part of ochem is the nucleophilic attack of the carbonyl SN2, so if you know that most of the questions can be deciphered...other than that, just know the O,M,P directors and activators, deactivators. Also, know how to determine the most acidic and basic compounds from a list...and know how to name sugars, carbohydrates and amino acids...