What is one way to check your writing for run-on sentences?

If a sentence is a run-on, correct it. if it is correct as written, write correct. 1.)i looked down. i saw that the well was apparently dry. 2.)we read the preamble to the constitution, our group felt anew the power of those words. 3.)the boy had trouble with the decimal point when multiplying he always put it in the wrong place. 4.)the thermometer broke, the mercury spilled onto the floor. 5.)i mislead my car keys, my house keys were also gone. 6.)it is against the law litter, neveretheless, people do it. 7.)ann threw away the check, but she eventually recovered it. 8.)i generally like the climate of the area where i live i do not enjoy subfrezzing winter temperatures. 9.)everyone should be polite, however many people are rude. 10.)i made my own chili to eat it one needs an iron stomach.