-Always start with the scripture itself. 
-Journal your thoughts and always consider the context of the writing, and where the thought of the writer begins and ends. 
-Then, go outside commentaries, and gain insight from other resources. I generally consider very conservative resources.
-Then go back and end with the original text.
-Try to form your own thoughts and not just adopt others. 
-One interpretation for scripture but multiple applications.  

KEY VERSE
Proverbs 11:20
[20] Those of crooked heart are an abomination to the LORD,
but those of blameless ways are his delight. (ESV)