Good morning! I cleaned my room yesterday. I want to keep my room clean. I want to get into the cleaning habit. Another solution would be to say "habit of cleaning". But "habit cleaning" is probably not what you want. It is grammatical but it just doesn't make a lot of sense. If you write "habit cleaning", "habit" becomes an adjective that describes the noun "cleaning". So "I want to get into the habit cleaning" would mean "I want to get into the cleaning, and the kind of cleaning I want to get into is 'habit cleaning'". I find it difficult to imagine a situation where that would be useful.