This is such a wonderful topic - thanks w2w for starting it! All of life is about learning what is most important, what works best for our own particular family putting unhealthy comparisons aside, and what to let go of to make things go more smoothly. I have learned these things one step at a time, and as we read each other's lists - I think that's important to remember - we didn't magically wake up knowing and understanding all of these things. Instead, it's probably taken years - even decades - to figure them out, and I bet in another few years/decades we'll have more insight to add to these lists. Here are my best tips for PEACE and SANITY - and I will add JOY to the list because that is something I am striving for in life as well.
*Think of homeschooling as a job, a high calling, and my most important thing to accomplish in a day. Share my faith at every opportunity with my dc (and dh).
*Have a quiet time with God sometime during the day. I try in the morning, but if I miss that, I don't go to bed without having done it. I make reading the Bible a part of this time as well as prayer. Also, when my relationship with God isn't right, nothing is right. If God is with me, who can be against me? When He is by my side, I am not alone.
*Stop answering the phone, being on the computer, having the t.v. on, etc. during homeschooling time.
*Limit my dc's social events. Our family is responsible for socializing my dc - we can be social together and have fun with this.
*Plan a schedule for each of the dc and stick to it. School is like my dc's job right now - and it is meant to be completed in a timely fashion, while still enjoyed.
*Know my needs - right now, I need one night away from home each week. I usually go out to eat with my sister one night a week, and we often watch a movie after that. I also need an errand afternoon since my dh does not run errands and is often traveling overnight on business. I have hired a homeschool teenager to watch the dc one afternoon each week. I get groceries and put all of my appointments during this time (haircut, dentist, doctor, chiropractor, etc.).
*Keep dating my dh - I try for twice a month, but it's usually once a month. This helps us stay in touch and be a couple dating again rather than just "mom" and "dad".
*Organize my home so it is conducive to homeschooling and our needs right now.
*Take time off in the summer for big projects and for training for the dc for things outside of school (i.e chores, routines, character issues, etc.).
*Have a simple breakfast/lunch menu that rotates.
*Have dc have an early bedtime. We've always done this - we start at 7:30 PM, talk a bit together, pray, I put toddler to bed, and then the older dc enjoy quiet time in their rooms until 9 PM (which they've grown to love). This is key for me. My dh is often gone, and this time gives me my sanity. If my dh is home, it's time for him to unwind too - and also time for us to catch up with each other.
*Pick a few close Christian friends and choose them carefully. Who I surround myself directly impacts how I behave. I only have a few friends I am close with, and they are wise ladies that lead me back to God in times of trouble. They don't allow me to be a complainer - they help me fix problems in a Godly way.
*Don't get caught up in gossiping about others or complaining - this means on the phone, on the computer, in person, etc. I think this is a tough one for most women. I have to make a concentrated effort to change the subject when someone is gossiping, and also make a concentrated effort NOT to complain and gossip myself. This only brings me and others down, and it is a sin. We all think someone else has the better life sometimes - the better house, the better husband, better kids, a better figure, a better relationship with God, a better God-given purpose in life, - oh this comparison stuff is destructive and it is NOT from God. When I choose to be positive, life looks better to me, and life IS better. No one has a perfect life, so it makes sense to quit wishing for someone else's life and make the very best of mine. This gives me PEACE and contentment and JOY.
*Take time to look nice. This means doing my hair, putting on some makeup from time to time, and wearing flattering clothes that fit. When I'm "put together', I feel more "put together", and my dh appreciates this too.
Thanks for starting this thread, and I have enjoyed what has been shared here so much already, and I am looking forward to all of the wise words still to come I'm sure!
In Christ,
Julie
Even so the enemy can still have his way with us if we allow it and life can just be tough. Let's admit it I am blessed to hs my six and have a perfect fit for us hsing is even at it's best work and this is a journey God takes us on that is not always just about learning for our kids. 
I often find it involves God's pruning of myself that I think is at least what a big part of it is about beyond educating my kids. And I find myself on my knees often asking if He could prune a little gentler. 
, if your kids have character issues