Cox was happy with Tuesday's 3-0 win over Farsley Celtic, his first as Pilgrims manager, but feels there's still plenty more to come from the side.
"What we want now is to create a situation where players go 'you can't drop me, I've got the shirt'," Cox said.
"People who know me know I'm not bothered about names or reputations. If you come in and work hard you set the tone and stay in the side."
Three points against visitors Chester today (KO 3pm) would see United maintain a play-off spot.
"There's not many times you get a job when the team are in the play-offs," added Cox, who is pushing his team to improve on the midweek victory.
"I know all about the place, I've known the chairman for a while, I know all about his ambitions.
"The group of players is good, but sometimes it's not about having a good group of players but a good team. I will always try to put out a good team.
"I want to see an improvement in certain areas. Let's talk in 10 games' time and see where we are in terms of does things need changing.
"I'll be more happy if we've won more games than lost in 10.
"There's a few more that could be coming back (from injury and suspension), it's a brilliant headache for me.
"Once we get one or two fit we get the strength in depth."
Jake Wright jnr, Jake Wright snr, Jay Rollins, Paul Green, Scott Garner, Andi Thanoj and Jordan Burrow will all be unavailable for today's visit of Chester.
Target man James Hanson will be available for selection again after being ineligible to face parent club Farsley.
"If I'm honest, it becomes brilliant," Cox added, talking about having a target man option available.
"All I've asked is for players to come in and do their best. The big man coming in, it'll be great.
"You look at the options (on the bench against Farsley) as people tire, you think 'I wish I could have this and that'.
"I think of Burrow and Greeny and think 'I wish I could put you on now'. So he's a great option."
The Seals - who beat United 4-0 in the reverse fixture - have picked up two points from their past four matches and five from a possible 15 under new manager Steve Watson.
United's leading scorer Danny Elliott could face his former side this afternoon.