Unsure of Convention for In-Text Citations
Generally, you cite a paper in the first occurrence of its matter and in occurrences where the matter is significant. 

For instance, suppose you are explaining about a method that is proposed in a paper. You cite it when you first state the method. After which it is understood that whenever you use the term, it refers to the one cited initially. If you are discussing two are more methods, explain each one separately by citing them and you also ought to cite at a tabulation during result comparison. Same goes for citing concepts; cite only when the concept is first introduced.

Other than that, citing for every sentence would be only be redundant and doesn't make the manuscript look neat either. If you do feel that you are in a position to have to cite nearly every sentence, then your content is probably largely of matter covered in your reference and not of your own. You ought to make appropriate edits in that case.