1. Make sure that you read enough of the previous verses and enough of the following verses to be sure that you understand what context something was said in.

A stepping stone for many performing Bible study is being able to discern what context certain words were said.  If something was said to the Jews it may not apply to the Gentiles and vice versa.  If something was said during the time when you had to perform actions to cleanse your sins it may not apply to the period where you are saved by grace.  An example is shown in Job where there are many chapters where Job's friends are giving him advice, but near the end God tells Job not to listen to them.  If you just read one verse or even one chapter you might accept this as God's word where if you had kept reading you would see that this is actually contrary to God's word.

Another place to use discernment is observing who actually said/wrote the passage.  For example, a large portion of the book of Job is a dialogue between Job and three other men.  So a large portion of the book is actually quoting what these other three men are saying to Job.  At the end of the book, God tells Job that these men don't know what they are talking about.  There are complete chapters in Job which are sayings from these men.  So if you just go to the book of Job and take out a verse you may be quoting something that God later says is foolishness.