Grammatical structures

Simple structures complex structures
affirmative sentences conditional sentences
negative sentences passive (progressive sentences)
interrogative sentence participle constructions
imerative reported speech
direct speech modals + perfect ("should have done")
modals present perfect/past perfect
basic tenses  

Versuche wann immer möglich komplexere Strukturen zu verwenden. Dies klingt besser und kann zum Teil auch mehr Informationen enthalten.