I want to restrict some users from seeing some Qlikview sheets in a ".QVW" file. What is the best solution for doing that?
See the options in Section Access.
There are a lot of opportunities for limit the users. You can see in the help of qlikview, in Qlikcommunity posts or in youtube videos. But if you use section access you have to be careful because there are options to lock the application.
Please refer to below post: http://community.qlik.com/blogs/qlikviewdesignblog/2014/05/26/section-access
You can provide control on sheet level with section access.
There are many ways to do the same like you can use section access, osuser() etc.
Have a look at below post.
Retrieving data ...