About 1/2 my income is on 1099s and 1/2 on W-2s, so I have not found it necessary to Incorporate or form an LLC. I file a Schedule C as a self-employed sole proprietorship and deduct business expenses on that.
I have started keeping a small separate checking account, with my own check card, to keep my travelling expenses separate from the household expenses.
Hire an accountant, who can help you categorize your expenses correctly. Best $500 I spend every year. I also file in multiple states, so it helps to have someone else checking all the correct boxes. There is also a book that I've found helpful "The New Tax Guide for Artists of Every Persuasion: Actors, Directors, Musicians, Singers, and Other Show Biz Folks" by Peter Jason Riley.
I keep a running spreadsheet in Excel to track my business related expenses. In March, I take my accountant the totals, and we review how long I was in each state, the per diem rates, my health insurance costs, etc.
Good luck! The first couple of years are a real sticker shock, if you haven't withheld additional on your W-2s or paid some estimated tax. Whatever you think you're clearing, the feds will want 25% (not to mention whatever state you live in). It can hurt, particularly when you needed that money to pay the rent last month...