Someone wrote that the Rebbe had said we should “never be satisfied with our past achievements.” The Rebbe crossed out the word “past.”
Some people tell you that if you’re never satisfied with your achievements, you’ll drive yourself nuts.
Ignore them. Look at whatever you’ve done and say, “If that’s good, double is better.”
Don’t let what you’ve done be the final measure of who you are.

Right now is the time to begin improving some small habit a tiny bit. By the end of the summer, we will have gained a new, better habit. We will then be ready for Rosh HaShanah, for we can say to Gd, "I have actually achieved my resolution for this year. I will make another resolution for next year and continue to grow better and better in my habits."
By choosing something small, we fly under the radar of the yeter haRa. We encounter no resistance, and we succeed in our intended growth.
In 2009, I resolved to stop eating sugar, cold turkey. That was a difficult one, but I succeeded and have not deliberately eaten sugar from that day to this.
But now I must find an easier resolution to achieve during this coming summer.
So should we all, to be ready for Rosh HaShanah.