The evildoers have sought to trap David. The "snares" (traps) have been meticulously laid in hopes of destruction. This could refer to physical traps, but I suspect it could just as easily refer to traps of words. Remember that David spent a good portion of his life on the run to stay alive. If there was one man in history who understood the danger of falling into a trap, it was David.
As we live for Christ, we can expect opposition (2 Timothy 3:12). The enemy will be there to thwart our efforts to be a good witness for God. The devil is a real enemy who seeks to devour you (1 Peter 5:8). We do not know what traps are in our path, but God does and therefore we ought to pray for Him to make us aware of those traps and guide us to pass in safety. He wants to be our protector, so why not trust Him for that role in your life?
This chapter closes with David asking God to cause the wicked to fall into their own traps while He goes free.