This is a question where I seek guidance from fellow/senior developers to get into my dream company - it's a pioneer in OOP and Agile.

I've already failed once to clear an interview. One part I feel most challenging is to come up with a proper Object Oriented design(classes, interfaces, methods, interactions etc.) in a very short time for certain situations like Pacman, Game Of Life and so on. As the problems are unprecedented ones - my approach is mostly to try different things and then make decisions - which they feel is not clear and not what they expect from a developer with 5+ years of experience.

I've already studied a few books on patterns, OOP - it didn't help me much and I think it'll take a bit more than that. Could some one please guide on what specifically shall I practice so that I can do better at design problems as above. I want to refine my approach and have a better thought process.