How can we improve on syncretism in missions?

2 Kings 17 partially describes the history of the Samaritans. In the Babylonian exile, the Samaria was replaced and re-populated by peoples of false religions. When the Samaritans returned from the exile they not only had influences from their captor's religions but now would blend in the religions of the people living in their homeland. The Jewish leaders shunned them so they would not be influenced by their syncretistic ways, and caused a hatred between the two groups.
Flash forward to Jesus...
John 4:1-26 tells of Jesus speaking with the Samaritan at a well. She is very aware that Jesus should not be speaking to her because of her people's mixed beliefs. In verse 23-24, Jesus says " But the hour is coming, and is now here, when the true worshipers will worship the father in spirit and truth, for the father is seeking such people to worship him. God is spirit, and those who worship him must worship in spirit and truth."
This is clearly a story of a people with mixed beliefs, causing them to be slaves to their sin. Jesus comes in and tells her that what she is doing and who or what she and her peeps are worshiping, clearly is not working(since she so quickly asks for the living water Jesus speaks of in 13-15). The story ends with Jesus' true identity being revealed and the woman leaving in praise.
I think it is interesting that although this woman's values and worship was mangled, she knew that a rescuer, or a Messiah would come and set everything straight. Well, here we are... Jesus' hands and feet. The problem many missionaries face when first going into a people group is syncretism. What a dreaded word... because we seem to not really know how to deal with it.
Firstly, we need to know the language, traditions, and past experiences of the group with other missionaries.
Language- because many only speak their native language, if a missionary were to come speaking in a similar or trade language, the people might not understand as well and only pick up on some of the gospel.
Traditions-many people only follow spiritual rituals and such because it is what they have been taught by older generations. Although these traditions may not be incredibly helpful to the people, they may be binding due to fear or superstition.
I read a story that told of how new missionaries discovered that the great success of a past missionary was not really so, because they simply added god to their old practices. So we need to understand where the people are at, and what they view God as truly.
some other steps we can use to avoid syncretism in missions are:
-some of their "spirits" are actually demons, who are worshiped out of fear, God can rescue the people
-know the origins of what they believe
-know the heart language
-give the message in the context of the peoples situation and not our own
-start with Genesis
-DO NOT try to turn them into the typical western Christian
-make it clear that God is the only God to be worshiped in spirit and in truth, sometimes being blunt as Jesus was in John 4 is necessary