Some synonyms may change meaning slightly depending on the context, so choose carefully. While 'quick' is a synonym of 'fast', in the context of 'quick meal', it does not mean exactly the same as 'fast meal'.
Pro Tip 2/3
Collocation Awareness
Synonyms may not always fit in the same phrase or context as their counterparts; be aware of collocations. You can say 'make a decision', but not 'make a choice'; although 'decision' is a synonym for 'choice'.
Pro Tip 3/3
Nuanced Meaning
Synonyms can convey slightly different feelings or degrees of intensity. 'Furious' is a synonym for 'angry' but indicates a higher level of anger.