The meaning of words can be influenced by their co-occurrences. Semantic prosody (SP) is attitudinal and evaluative meaning inferred from the habitual lexical environment of a word in a corpus. By introducing SP in an English teaching classroom, teachers can reveal more implicit knowledge about language usage and assist students in reaching sufficient English language competence. This paper offers a detailed study of semantic prosody and suggests an approach to vocabulary instruction by making use of research results obtained in a native English corpus. On the basis of corpus-assisted methods, this study documents a series of pedagogical interventions such as SP instruction, tests, surveys and interviews, which are centred on using SP in synonym differentiation. The pedagogical implications are to raise the awareness of semantic prosody among English learners and encourage them to explore more idiomatic and natural use of English vocabulary by studying collocational meaning in corpora.