The trick I've developed to improve my commit messages is to ask my self how would I explain something to do what the commit does, in a widest sense. Before that my messages either amounted to "HAAAAANDS" (https://xkcd.com/1296/ -- there is always an appropriate XKCD), or tended to go into minutiae of implementation ("added a boolean attribute 'foo' and changed method 'bar' to raise FooBarBazException when the calculated value is 42"). The "instructions" approach helps me focus on why something was done ("implement verification of the IMO field") than how (which should generally be obvious from the code itself).