Let's start with a victory
When Ole Solskjaer took over Man United from Jose Mourinho, the atmosphere at that time was very gloomy. Many players lost faith and motivation, no one believed Solsa could revive everything so quickly.
Ole's start was a 5-1 victory over Cardiff City. After that, the Norwegian coach won 14 more matches out of a total of 17 interim matches. The only defeat (besides 2 draws) was the defeat to PSG in the first leg of the Champions League round of 16. Then in the second leg, the "Red Devils" made a perfect comeback.
It is not yet known what the result will be from now until the end of the season, but Carrick should start with a victory against...Man City to revive the team's spirit. If he can do that, the inspiration will be very high.
Do not make thoughtless statements
Press conferences with bad moods have harmed Erik ten Hag and Ruben Amorim many times. Even once Amorim said that Man United is currently the worst version in club history. The saying is not yet known to be true, but it has touched self-esteem, from the team's leadership to fans and players.
In 2018, Solskjaer once said that coaches must be cautious in their statements. In the generations of captains after the Sir Alex era, only Solsa was the most cautious and humble person, the rest mostly made verbal mistakes.

Before Amorim, Ralf Rangnick once became angry in 2022 when talking about shortcomings in the squad. The German strategist at that time shared that he could not solve all problems in just 2-3 years and the only person who could do it was the club leader.
There are countless other slips of the tongue from people besides Rangnick, Ten Hag and Amorim, but in general, too much pressure at Old Trafford easily makes coaches lack control of words and disasters often come from there.
Need to be calm to decide everything
When Man United sacked David Moyes in April 2014, it was the first time since 1986 they sacked a coach. Sir Alex Ferguson replaced his predecessor Ron Atkinson in 1986 and it was not until 3 years later (1989) that the Internet was born. Saying that to show how long Sir Alex's era was.
After Moyes was sacked, Ryan Giggs was promoted to interim. Everything Giggs did at that time was very gentle, intervening in a non-"bold" way. Everything was kept at a temporary level by Giggs until Louis van Gaal arrived and took office.

You should not try to stay too long if you are not qualified and lucky enough.
Not always staying for a long time is the right decision even if you do your job well.
After a great interim spell, Solskjaer was officially signed in March 2019 and he only won 2/10 matches afterwards, until the end of the 2018-2019 season. The following seasons were slightly better when the team finished in the Top 3 and reached the Europa League final.
However, everything collapsed in 2021 and Solsa had to leave his seat. After that, his coaching career was very unsuccessful and unsuccessful.
When Carrick took office, Man United had 2 wins and 1 draw. BBC Sports then also posted a message, the 3-2 victory over Arsenal was a perfect farewell. Later, Ruud van Nistelrooy also took office in 4 matches and won 3 (a rate of up to 75%, the highest in history). After that, Van Gol also left with beautiful memories and added very impressive professional lines in his personal profile.

You should use what you have well
Carrick has pledged to use available personnel and play continuously with what Darren Fletcher used in the 2 interim matches. Man United leaders also really like the 4-defender formation and use young players like Fletcher did.
Many Man United players, typically Kobbie Mainoo, were dissatisfied with Ruben Amorim when he was not allowed on the field. Under the hands of Fletcher and soon Michael Carrick, Mainoo will return regularly. That is how interim coaches used to do to keep the team's internal situation stable.
We shouldn't always talk about heroic history
Man United has a very proud tradition but the past "cannot be peeled to eat". Giggs and Solskjaer have talked a lot about the team's history, this is good but should not be abused.
What Carrick needs to say in parallel with the players at this time, besides tradition, is the current status of the club. From there, everyone will have the most realistic view to overcome the current difficulties together, avoiding being immersed in the past.
It's a bit of a bit of a bit of a bit of a bit of a bit.