Dey, I. (1999).
Grounding grounded theory: Guidelines for qualitative inquiry.
CA: Academic Press.

Develop meaningful categories from emergent data and use "theoretical sensitivity" that is from a theoretical lens but without privilege to any particular point of view. When evidence is consistent with a theory, apply it.

Use many methods, begin with unstructured method, dialogue between data and analysis; with theory, focus observations.

Analysis is in 4 stages: generate and combine categories and properties, then delimit categories and write theory.

Explicit in this approach is the verification of hypotheses as they emerge. An invaluable source is knowledge fo extant theories as part of analysis of data and emerging theories. This is by nature a hybrid methodology.