They are used in positive sentences: She almost/nearly/practically missed her train. They can be used before words like all, every and everybody: Nearly all the students have bikes. ◇ I’ve got practically every CD they’ve made. Practically is used more in spoken than in written English. Nearly is the most common with numbers: There were nearly 200 people at the meeting. They can also be used in negative sentences but it is more common to make a positive sentence with only just: We only just got there in time. (or: We almost/nearly didn’t get there in time.)
Almost and practically can be used before words like any, anybody, anything, etc: I’ll eat almost anything. You can also use them before no, nobody, never, etc. but it is much more common to use hardly or scarcely with any, anybody, ever, etc: She’s hardly ever in (or: She’s almost never in).
Almost can be used when you are saying that one thing is similar to another: The boat looked almost like a toy.
In British English you can use very and so before nearly: He was very nearly caught.
(from Oxford Dictionary)