First, it's always good to have higher income, so enjoy that!
It sounds like your daughter actually is your dependent. This is based on specific tests, not a family's discretion. So if you don't claim her as a dependent, be sure you can justify it according to the rules. Note, however, that families do have a fair amount of discretion in giving each other gifts, which are not counted as income. (Again, be sure you document and can justify whatever you do.)
Since income is usually determined before the end of the tax year, you can't do too much to change that. There are only a few specific things that might lower your income after the year ends, like deductible HSA and IRA contributions. So most of the tax planning you can do will have to be for future years. It is often possible to move income between years in different ways (by planning in advance.) Like you note, often the best tax planning is to keep your income level or gradually increasing rather than fluctuating a lot from year to year. If tax planning doesn't strike you as DIY, a good accountant might be worth consulting.
