This tip is an offshoot of yesterday’s, which related to maintaining a strong sense of space and time. Flashbacks are often important to your story. They provide background, either to events or the character’s experience base as it relates to the plot. Entering and exiting a flashback properly is important, again so you don’t lose your reader.
Thus, if you end a chapter or section with a flashback, be sure to take the reader back to the present so they’re not lost when the story returns to its normal time frame. This can be done at the flashback’s conclusion or at the beginning of the next section, whichever works better. It goes without saying you should do this clearly if it’s mid-section or mid-chapter as well.