The Rams have moved quickly to bolster their ranks over the summer, with deals wrapped up for Lee Grant, Craig Forsyth, Chris Martin and Johnny Russell.
Clough feels he now has 'most positions' covered and will only look to make minor tweaks ahead of the 2013/14 campaign.
Former Watford midfielder John Eustace is training with the club and could earn a contract, but Clough admits any further additions will depend on departures.
He said in the Derby Telegraph: "We'll see what happens with John but I think we are covered in most positions at the moment.
"We are happy with the numbers and the depth and it will depend on the outs if we are to bring any more players in. But there is no point bringing anyone in if they are not going to improve us.
"Look at what we have in most areas of the pitch now. We have good quality and reasonable cover, so any new signing would certainly have to be challenging for a first-team spot.
"Is it our strongest squad yet? Yes, I think so. The only two we are missing through injury are Shaun Barker and Mark O'Brien. If we had those two available we could definitely say it is our strongest squad."