Self recognition of the affects of a piloting absence are an important beginning. Those first few refresher flights should either be supervised by a current qualified pilot, or based upon a lot of experience and self awareness.
Two of the more skill and technique demanding types of flying are water and ski flying. As it is here in Canada, your opportunity to maintain currency is seasonally limited - and global warming is affecting that! That first float flight of the season, I pay very close attention to myself. Happily, this year, I enjoyed a float flight in Norway two weeks ago, which was a beginning of my having to give seaplane rating training later this month.
The other aspect I find worthwhile, is that I practice emergencies a lot, and in different types of aircraft. I meet many pilots who fly the regular hamburger runs, but when it comes up for discussion, have not flown a forced approach, nor unusual attitude recovery, in recent memory. Currency is one thing, breadth of currency is another....