BLUF[1]. Put the key point you want to convey (or question you want answered) in the very first line of the E-mail, in boldface or color or whatever as the TLDR. Then go into detail further down, that you know your colleague may or may not read.
Don't mix topics for these people. Send multiple E-mails. Chances are, they use their Inbox as a TODO list, and if they have an E-mail with multiple topics it could get lost.
Don't mix topics for these people. Send multiple E-mails. Chances are, they use their Inbox as a TODO list, and if they have an E-mail with multiple topics it could get lost.
1: https://en.wikipedia.org/wiki/BLUF_(communication)