Contending for the faith once delivered begins with praying in the Holy Ghost, keeping oneself in God's love, looking for His mercy unto eternity, having compassion for some, making the difference, saving some with fear, hating even the garment spotted by the flesh. The fact that we would have to contend with others supposedly within our own faith means that it is not an easy list of things to do. We are warned that these apostates have crept in unaware and that there is a certain advantage and admiration inherent for them to do so. They are defined as dreamers defiling the flesh, despising dominion, speaking evil of dignities. They preach out of what they know naturally.
Compare this with 2Peter. In kjv@2Petter:1:5-8 contenders for the like precious faith begin by adding to their faith virtue (valor towards excellence) knowledge (revealed, spiritual) temperance (against similar brute knowledge) patience (persistence) godliness (living forward, spiritual obedience) brotherly kindness (striving for the unity of the Spirit) and charity (Agape love).
2012 - pBiblx2 Field Wise Bible System Version 2.0.9d - GPL3