I thought I would mention a little trick.
Suppose your ideal for a macro is 's' (s:) but s is already taken, then you might be inclined to use a second letter, such as 'sz' (for size).
In my experience the next best after a single letter is in fact the letter doubled, because your finger is already on the key concerned, so after 's' my macro would be 'ss', and this concept can be applied to the rest of the alphabet. When I search for a plant genus, I use gg: rather than e.g. gen:
d