Steve Bruce's side, who face the Hammers at the London Stadium on Saturday afternoon (kick-off 3pm GMT), currently sit one point above the relegation zone after last weekend's 1-1 home draw against Wolverhampton Wanderers.
And Schär, who is a doubt for the Magpies' visit to the capital, believes his side must take the positives from 1-0 victories against Spurs and Man United, with the Swiss defender starring in both triumphs against two sides competing in Europe this term.
Schär said: "In the past, we beat Tottenham and Manchester United but we lost against Norwich who are behind us so it's difficult because you could win or lose against each team. We know each week is always a tough game but we know the teams who are near us in the table and we will compete against them to get points and we will work hard to do that.
"West Ham have a decent team with a lot of quality players. For me, they should be higher than they are at the moment but it's still the start of the season, more or less. They have some new players and it's going to be a difficult game, especially at their home (ground). We have to be ready and hopefully we will get something.
"Away (from home), we play more of a counter-attack but for example, in the Wolves game, we had decent possession in the first half. We are able to do it but we just have to try it and believe in ourselves, especially at home. Also, the fans are wanting and expecting to be on top of our opponents.
"We need to keep working hard. I really believe in our team and the quality we have, even when we are struggling. I know we can do a good job and we have shown this against big teams.
"We have to take the games against Tottenham and Man United as a reference to try and always play like this. If we do that, I am sure we can improve and gain more points."
After a mixed start to the campaign, which has involved facing five of last season's top six, United have obtained six points more after their opening ten league fixtures in comparison to last term.
However, Schär admits there is plenty room for improvement for his side ahead of the top flight clash against Manuel Pellegrini's side, with Newcastle netting six goals after ten league outings.
The 27-year-old added: "We had quite a hard start to our programme against five of the big six teams and some difficult games. The good thing is we got six points against Tottenham and Man United so I think that is very positive.
"We haven't scored many goals this season so we'll want to improve on that and be more powerful. If we can score some more, I think normally our defensive work is quite good.
"We've had one or two bad games but I think we are quite strong. It was a hard start to the season and we're still looking game by game and need to focus on the next game against West Ham.
"We know what we want and what we can improve on to do better. We know we have a lot to work on but we have a lot of confidence in our team. We have quality - we have good players and have a strong team. We will all work together to go in the right way."
