Start paying attention to what interest your child and encourage them in that area instead of trying to make them fit into a mold God didn't intend for them. I can say that this has been a big one for me. I have 3 totally different boys. One who has a laid-back comedian type of personality who loves to work with kids. Another son, who loves music, art and cooking. He is not driven when it comes to sports, unlike my third son who is very competitive with sports. And quite good at it, if say so myself! I would never be able to get my first son to excel in art, just as I would never dream of making my second son do something sports related and expect him to be the team star. Find what interest them.
When it comes to motivation, instead of always pointing out the negative focus on little improvements. This will give your child the confidence to try harder. If they always here negative they WILL give up. Make sure your expectations are realistic for their age. In the book the author suggest you make a list and evaluate each expectation.
For older children talk to them about their ambitions. I know in our family we talk a lot about the future and about their future wives. We try to get them to think about what kind of husband and dad they want to be. Focus on learning not strictly on grades. It's learning that matters. Well... and Godly character that matters most!! Encourage your child to ask questions and take the time to answer their questions. This can be hard. I have one son who ask A LOT! of questions and sometimes I have to admit I lose patients and give them a short "I'm too busy" answer.
i'm workin on it!
The most important thing is to be patient. Waiting is not a passive action. It's active. It take a great deal of energy to restrain the impulse to push, shove, insist, and suggest when you see a lack of progress. The bottom line is to encourage the little victories while guiding them when they are heading the wrong way without making them feel like a failure. Your optimism in them can overcome their feelings of failure. Failure is temporary if you have the courage to get up and try it again!