Personally, I believe that to be “dead to sin”, as described in Scriptures, is much like telling someone “You’re dead to me”. Not saying that the person LITERALLY ceases living, but rather that in to you and in your daily life, sin has gone from pleasant to abhorrent - it indicates the Spirit has given you a “change of heart”, and that rather than fixing your eyes on sin, you have been turned to fix your eyes on Christ. Mistakes will certainly be made, as the best of men is still man at best (Spurgeon), but it means that your priorities have shifted from sin to Christ.