First home office based job, have questions on deductions...

I started my first home office based job and I am lost on how to maximize my tax deductions from this. I am curious if moving back into a 2 bedroom apt would benefit me come tax time. I am currently in a 680 sqft apt, which a "home office" of about 30 sqft, so that means I can deduct roughly 5% of rent, utilities, insurance, etc right? If I move back into a 2 bedroom where the rooms are the same size and I use the spare as my office could I deduct 50%? It's a $150 a month difference in rent, just curious if I would get that back come tax time if I do upgrade.