You can continue to file Schedule C for your business even without income. It will make it easier when you do have business in 2019. Do go through the expenses to make sure you aren't taking any that you did not have such as vehicle and home office.
You can deduct expenses as long as you can prove that you opened or were in business in the year expenses were incurred. To be deductible, a business expense must be both ordinary and necessary. Please note that if you do not have profit for three out of five years, IRS might question your profit motive.
If you have other questions about this, ask in the comment section below.
