There are many different types of casual conversation, because there are many different personalities and many different situations. For example, some people like to sound smart even in casual conversation (for sake of argument, let's call this "semi formal" here), and some people like to sound humble even in hyper formal contexts. Since there are so many options depending on what you're really looking for, I'll focus on the first sentence...
I much prefer watching films at the cinema rather than at home. (This can be formal or semi-formal)
I much prefer watching films at the cinema instead of at home. (This is semi-formal, and a bit less classy than the previous option)
I prefer watching films at the cinema much more than at home. (This is semi-formal, and a bit less formal than the previous options)
I like watching films at the cinema much more than at home. (This is truly casual, informal, basic language - not trying to sound sophisticated at all, but is no less grammatically valid and is no less charismatic than the previous options)