I haven't used MM acrylics either, but from the experiences of many people here, I'd be thinking that a primer would be recommended and a well cleaned surface essential. I also concur with the others here - make sure that your pant is well stirred. (Unlike 007, stirred, noyt shaken)
Levon
With Tamiya, once I dip my brush in the bottle, I then dip it in their thinner, and it has worked well for handbrushing. However, the smell of their acrylic paint can be overpowering inside the home. I like enamels,but again, the smell is too toxic inside our home because of my son and wife. Any tips would be great for MM Acryl. Thanks.
I don't find the smell of Tamiya acrylics too offensive. If you want an acrylic paint with no smell at all, try Vallejo - Their Model Color line brush-paints far better than Tamiya acrylics.