England scored five tries in beating France 34-10 at Twickenham on Sunday, but Tigers scrum-half Ellis feels there is still room for improvement.
Ellis, who has started every game of the Six Nations, is in the side to take on Scotland and he said: “We are keeping our feet firmly on the ground. It was great to win well on Sunday but we still need to improve.
“We are raising the bar every time and we want to keep going. We are putting the hard work in on the training pitch and hopefully it will come off again on Saturday.
“Scotland have quality across the board and last year’s result against them shows how well they can play. We will need to defend as well as we can.”
Ellis was backed by his Tigers teammates Tom Croft and Toby Flood, who are set to start alongside him at Twickenham on Saturday.
Croft made his first international start against Scotland at Murrayfield last season, and he feels England can get better.
The Tigers flanker said: “Playing Scotland is always a tense occasion. I had my first start for England against them last year and it was a massive match.
“We need to build on what we achieved on Saturday. We dropped off towards the last 20 minutes and we can’t let that happen this weekend. We played well against France but we still have more to offer.
“Individually these players are the best and when you bring them all together you can create some fantastic rugby, and that’s what we hope to do on Saturday.”
Flood is recovering from a shoulder injury he picked up in the win over France but has been selected to partner Ellis at half-back.
He said: “I’m feeling good, the shoulder’s doing fine. I’ve been training well and I’m looking forward to starting on Saturday.
“Scotland will be a strong, physical challenge. We can’t rest on what we achieved last week. We need to prepare for this Saturday mentally and physically.
“We have raised the bar now but we need to continue that development, we can’t just sit back and relax.”