Since I believe no question should pass unanswered, I'll try to help you with this one. And because yours is of rather general character, I'll narrow my reply to just two examples of words that I find extremely useful in everyday English:
No 1: 'stuff': I love this word since it means nearly anything you want.
'It's my favourite stuff' (about a particular brand of beer).
'I'll get my stuff and go home' (collect my things, luggage, etc.).
'To get the office working you'll need a computer, fax, photocopier, stationery and stuff' (Other similar items).
No 2: 'Thingummajig' is another 'wild card'. It looks great, sounds great and is fun to use because you simply substitute it for a word you don't know or can't remember at the moment.
'To fire the shotgun you just pull the ...thingummajig..., ah, yeah, trigger it is. So you pull the trigger.'
WARNING! Depending on the context, it may or may not work the way you want it to.