One thing that helps with shifting is to use good, fresh, engine oil. The transmission and engine share the same oil, so if the oil hasn't been changed lately, I suggest changing it, and use a good synthetic oil that is intended for ATV's like Shell Rotella T6 or Honda oil. Whatever oil you use, make sure it has a JASO MA rating. Oils of that type are compatible with the wet clutch found in Honda ATV's.
Also, a good, strong battery is important in making shifts happen on an ES machine. I found that out on my 2000 Rancher. If you don't know how old that battery is, just buy a new one.