Several of these are questionable or partly questionable. For areas that I question, if the OP wants to come back with reputable sources I think that would be great.
1. Yes, the Augusta rule is real. However, I think the IRS would have issues with renting it to your own business.
2. Approximately true. But spending $100 on any of these expenses to save perhaps $25 in taxes means it should be viewed as a "self employed discount" rather than a way to save money. You're still out $75. Also, there are rules and restrictions that need to be considered for several of these items.
3. Approximately true. There are particulars, see
https://www.irs.gov/businesses/small-businesses-self-employed/family-help. You can get in trouble over paying them excessively. Oh, and Roth IRA limit is now $7K.
4. Yes, there is a Section 179 deduction. But again, you're spending $50K on a truck and saving $12.5K on taxes. You're still out $37.5K (plus gas/maintenance/repairs/insurance/etc.) It's a "self employed discount".
5. Approximately true. The IRS is on to this tax dodge, though, and you're required to pay yourself a reasonable salary and pay the appropriate SE taxes.
6. States differ in the level of taxes they collect and in the level of services they provide. They also differ in how they collect those taxes. So you might not pay income taxes, but your property or sales taxes or estate/inheritance taxes may be higher. Or you might not get the level of services you want. I think Alaska and Nevada are slightly different because of the oil and gambling revenues, respectively.
7. See Augusta rule under item 1; it sounds like this is a duplicate. If you're not invoking the Augusta rule, then I don't believe the rental income would be tax free.
Other ideas:
8. 529 plans. Often a state tax benefit, tax free growth, tax free distributions for higher education expenses, leftovers can be rolled to a Roth IRA.
9. Saver's credit. Lower income folks can claim the credit on Form 8880.
10. HSA. Tax deductible contributions, tax free growth, tax free distributions for medical, lightly taxed after age 65 for non-medical.
11. Roth conversions. Voluntarily converting funds to a Roth in a low tax bracket now can avoid paying higher taxes at RMD/SS time.
12. Annual gifting. Some folks here are going to have problems with the federal (and perhaps state) estate tax system if the TCJA doubling expires on 1/1/2026 as scheduled. Annual gifting gets those funds and future growth out of your estate.
13. Save wage income and then invest. Wage income generally has income and FICA taxes. Unearned income avoids FICA taxes. LTBH investing avoids income and FICA, and LTCG rates are lower than ordinary income tax rates and are only incurred when you sell.
14. Buy index funds. Minimal to zero capital gains distributions, usually no short term capital gains distributions, and low distributions otherwise, most of which are qualified, which all reduce tax drag.
15. Track your business expenses. Related to item 2 in the OP, you should only deduct what you can substantiate. Keeping organized and knowing the rules helps you get the best outcome.
16. Spend money carefully. Any money you spend is generally money you have to generate from income (major exceptions are gifts and inheritances), on which you have to pay income and FICA taxes. If you spend $1, you probably have to earn $1.50 to have the $1 after taxes to spend it, not to mention the money and effort and time you spend to earn the $1.50 in terms of commuting, clothing, stress eating, etc.
17. If you have kids in higher education, read IRS Pub 970 to learn about all the various tax benefits (529, AOTC/LLC, scholarships, etc.)
18. Pay attention to tax law. It changes every year, and sometimes the changes are ones you can take advantage of. For example, I have some leftover 529 plan money for my kids. I was going to distribute it to them, but that would have incurred some taxes. Now, with the new 529->Roth rollover option, I can avoid those taxes and get those 529 funds into their Roths.