what link building methods I should use?

I got a client, who has many clients. these client's clients, some of them are big names. I know, there are many ways to build links. however, I do not want to screw this and want to play safe since there is so much potential.
so, which method should I use? article is ok, directory is ok. what else? I know blog comments, probably, should not use for this moment since will have to use SB to sp*m too many sites. how about profile links? I do not mean thousands thousands, maybe 100 to 200? should it be ok?
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