Documentation comes before collection, and the sequence in the manuals is always the same: notes, then photography, then sketches and measurements, then recovery.
Notes. Written as you go, not afterwards. Time of arrival, weather, lighting, who was present, what was said by whom, what you did and when. A note written from memory at the end of a shift is a different kind of document from one written at the time, and the difference is visible.
Photography. Three distances for every item that matters: the whole scene, the item in its surroundings, the item close with a scale beside it. Photograph before anything is moved, and photograph again if something has to be moved to reach something else.
Sketch and measure. A photograph shows appearance; a sketch fixes position. Two fixed measurements to permanent features give a point that can be re-established after the scene is gone.
Then recover. Each item into its own packaging, sealed, signed and labelled with what, where, when and by whom. An unlabelled bag is not evidence; it is an object.
Source. NIJ NCJ 178280, Crime Scene Investigation: A Guide for Law Enforcement, sections on documenting and processing the scene.