The 26-year-old put himself back in the England frame after starring for Sale last season and helping the club qualify for the European Rugby Champions Cup.
Cipriani also impressed when he made a cameo appearance during England's tour of New Zealand earlier this year.
However, head coach Stuart Lancaster has opted to select Owen Farrell, George Ford and Stephen Myler as his fly-half options for matches with the All Blacks, South Africa, Samoa and Australia next month.
Cipriani is refusing to be downbeat about his exclusion, though, and is promising to work harder to be selected in future squads with next year's World Cup in sight.
"It's disappointing but it doesn't change daily habits. I'm still trying to get better every day in training and in every day," he told Sky Sports.
"If that's my focus on improving and throughout the season I keep improving, hopefully by the end of the year I'll be better.
"There are options in all positions when it comes to selection and I think that's a great thing for the England selectors - they have so many great players to pick from.
"I've just got to get back to getting my head down and make the right sounds on the field.
"I think with every English player, all they want to do is represent England. It's the biggest honour in the game and I think it's just important to keep doing my day-to-day work and keep my habits good."