The way you parent your children will change over the years. Certainly, you can see changes you've made between how you raised your first child and how you raised your last. Hopefully, the improvements you've made to your parenting style happen early on in your child's life, rather than after they've moved out of the house.
But regardless of your parenting style (or if this is your 1st or 5th kid), there are some things you should never say to your child:
No one likes to argue with a child, especially if it's to get them to do something they don't like (taking medicine, going to the doctors, taking a test or thousands of other unpleasant things come to mind). However, phrases such as "this won't hurt" or any other lie shouldn't be said to your children. Remember, parents are role models. Your kids will learn to lie if you do.
2. Do not say yes all the time
Every responsible person wants the best for their kids. But love is not measured by giving into your child's every desire. It is actually quite the opposite. Your child needs limits...but beware of saying "no" all the time too. You wouldn't want to limit your child's creativity by always shooting down their suggestions.
3. Do not label
Are you familiar with how a sponge works? Children are the same way. Everyone has imperfections. While you don't want your child to think they are perfect and can do no wrong, you also won't want to raise children who feel defined by their imperfections. Be encouraging and supportive - and don't ever label your child.
4. Do not compare
Your child is already struggling to get your attention every day. And when you compare them to others (your brother was already playing piano at your age, your friend is the best soccer player, why can't you study like so-and-so) their self-esteem takes a hit. While you can point out the success of others, don't compare your child's faults or shortcomings to the success of those around them. Comparisons still hurt teens and adults too, so don't think comparison is a tactic you can use when they get older.
5. Do not criticize
No matter how bad the drawing, praise your child's creativity. Your child will get enough hurtful criticism from others in their life. Encourage your child by showing off their accomplishments to others with pride. Avoid condemning their achievements, appearance and choices.
Swearing, indecent jokes, talking badly about others and complaining about everything are things you should not say in front of your children. They are always listening and are likely to repeat what you say.
7. Do not blame
The house is a mess and your child is probably responsible. But if you manage the situation without blaming your child, you can feel peace in your home. Don't place blame on such young shoulders.
Above all this, love your child. You are bound to slip up and make a few mistakes, but if you have a home full of love and support, those mistakes won't matter as much.