Naomi,
I am a CPA located in Las Vegas. My niche is small businesses because I understand and relate to them. These are great questions. And the same ones that small business owners run into everyday.
There is no one answer because the treatment of these depends on your specific situation. I can briefly help you. All of these can be completlely deductible even if your business has a loss. Home office: If you have a room dedicated to running your business operations and/or administrative stuff, claiming a home office deduction is completely acceptable. Even if you spouse or children venture in there once in awhile, it is still Mom's office. You can't claim a home office deduction though if you have another office that you go to everyday for business and just use the one at home in the evening.
If you can keep track of your business miles (or reasonably estimate), great. If you have an outside office, you can't count miles from your home to the office as business. These are technically commuting miles. But if you work out of the home, every trip relating to business is counted.
Cell phone: if needed for your business, absoultely 100% deductible. But watch that you don't include spouses or kids phones.
Computer/Equipment/Furniture: It is best to determine your business percentage. you can depreciate or write off the cost of these at the business %. Even if you had it before, it can be put into service as business assets at the start date.
Hope this helps. The IRS is watching what they call hobby businesses. They look at intent. If your intent if to make a profit (eventually), it is ok to have a loss. If you want to talk further, you can go to my website
www.kkwlv.com for all my contact info.
Kelly