To truly avoid any allegation of plagiarism, one would separately cite every sentence whose idea has been taken from elsewhere. In my field though, many journal editors will not accept this amount of citing. The arguably acceptable alternative is to provide just one citation for several consecutive sentences that are derived from the same source. Usually this is placed at the end of the last of the related sentences. A reader cannot be sure though as to how many of those sentences come from that source, leaving the author open to charges of plagiarism. I am referring to paraphrased material, not direct quotations. Any comments or advice? Thank you.
You could quote a block literally and cite once. You could then use your own words to summarize if you think it needed. This separates your words from the original.
For long runs of literal citations you could use indented blocks and block shading/coloring (if allowed) rather than just quote marks.
You could also use the paragraph structure. Start a new paragraph with "We learn from AJ Smythe that" ... followed by your paraphrasing of good ol' AJ. Then end that paragraph with your citation(s).
Think about what you would do if you had to provide a translation of Smythe from the original Hungarian instead of a paraphrase. Quoting with quote marks isn't quite the right thing, but indented blocks might be.