{
lcd.print("hello");
lcd.setCursor(0, 1);
lcd.print(millis()/1000);
}
These curly braces are unnecessary. You should remove them.
if (millis()/1000 >10)
lcd.clear();
The body of the if statement is the single method call to clear the screen. Is this what you intended?
This code:
{
lcd.print("hello2");
lcd.setCursor(0, 1);
lcd.print(millis()/1000);
}
is unconditionally executed. Is that what you intended? If so, the braces are unnecessary. If this is supposed to be the body of the if statement, some code rearrangement is in order.
The millis() output keeps counting up. After 10 seconds, the statement if(millis()/1000 > 10) will always be true,
I think that what you want to do is measure the difference between now (what millis() returns) and then (some previously stored millis() output) and compare that to 10000. Comparing to 10000 is faster then dividing by 1000 and comparing to 10. You should get in the habit from the beginning doing things as fast as possible, so you don't develop bad habits. You are off on the right path not using delay(), so unlearning that bad habit won't be necessary.