You can have about 80% cbet and still win at NL10. This doesn't mean it's the best percentage. I think most solid players have aroun 70% like booomm suggested.
To increase your cbet, you can start by cbetting all heads up flops that don't have the following structure (all at the same time):
1. 2 cards of the same suit.
2. 2 connected cards lower than Q (like JTx)
3. The 3rd card is between 5 and T and doesn't pair the previous 2.
Basically, the flops I'm referring to are the double suited 589, 678, 6TJ, etc. that will almost always hit your opponents range so you will not get enough folds on.
If it's monotone you can cbet at the same frequency as dryer flops because he will play face up usually.