The following are grammar issues you should be solid in at this point. There are links to help you if you are not feeling confident with that grammar point.
Cases:
Nominative
Accusative
Dative
Prepositions:
Accusative: durch, für, gegen, ohne, um
Dative: aus, ausser, bei, mit, nach, seit, von, zu
Either/or: an, auf, hinter, in, neben, über, unter, vor, zwischen
Adjectives:
Adjective Endings
Comparatives & Superlatives
Verbs:
Present tense
Perfect Tense (hat geverbt past tense)
Preterite Tense (one word past tense—war/ging/ wohnte)
Future Tense
Conditional with würde
Types of verbs (separable prefix, stem changing, wissen/kennen, modals, reflexives)
Conjuctions & Word order
General word order (SVTMP)
Coordinating Conjuctions (und, aber, oder, denn, sondern)
Subordinating Conjuctions (verb pushers)
Zu+infinitive clauses
Other:
Du vs. Sie vs. ihr
kein vs. nicht
da & wo compounds
Cases:
Nominative
Accusative
Dative
Prepositions:
Accusative: durch, für, gegen, ohne, um
Dative: aus, ausser, bei, mit, nach, seit, von, zu
Either/or: an, auf, hinter, in, neben, über, unter, vor, zwischen
Adjectives:
Adjective Endings
Comparatives & Superlatives
Verbs:
Present tense
Perfect Tense (hat geverbt past tense)
Preterite Tense (one word past tense—war/ging/ wohnte)
Future Tense
Conditional with würde
Types of verbs (separable prefix, stem changing, wissen/kennen, modals, reflexives)
Conjuctions & Word order
General word order (SVTMP)
Coordinating Conjuctions (und, aber, oder, denn, sondern)
Subordinating Conjuctions (verb pushers)
Zu+infinitive clauses
Other:
Du vs. Sie vs. ihr
kein vs. nicht
da & wo compounds