Manager Mark Warburton insists Rangers' January arrivals will have to earn their place in the team.
Kenny Miller scored a hat-trick as the Scottish Championship leaders beat Dumbarton 6-0 on Saturday to remain three points clear.
"No player comes in and walks straight into the team," said Warburton.
"A lot of work has been done already and a lot more work will be done because we said we'll strengthen and bring in players, and that's what we'll do.
"We want to get our business done early and hopefully we'll get a lot more done this week.
"You saw the commitment of the players and whoever comes to the club has to justify their position in the team."
Martyn Waghorn, Andy Halliday and James Tavernier were also on target in Rangers' win over the Sons.
"It was a very satisfying display," said Warburton. "This is a difficult place to come and the pitch was really heavy and the wind was blowing.
"We spoke before and after about the importance of building on the win and the performance against Hibs [on Monday].
"That was the message. Whether there are 52,000 inside the ground or just 2,000, nothing changes. It's about the standards, it's about dominating the football and getting the rewards."
And, on Miller's performance, the Englishman added: "Kenny can't let his standards drop and he knows that.
"His contribution on and off the pitch is so important and I thought he was excellent."