Take Great Care -  do not slip un-noticed into becoming a "cardboard minister."  Beware of starting to use "stock phrases" and having "stock scripture" at hand for different circumstances.  LET THE HOLY SPIRIT WORK IN AND THROUGH YOU.  Know that there is a huge difference between being a sermonizer and being a minister--pastoring as a calling.  Go into retreat diving deep into the Word, Solitude, Prayer, as well as Divine Fellowship for three to four weeks per year if at all possible.  And if you find yourself drifting into stock-phrases, stock-scripture, or robotic automatic-pilot pastoring, take at least a month (or more) to go Up to the Mountain Top with the Holy Spirit - and then return and be a Divine Refuge in the storm for all thy Brethren.  Love One Another.  Love One Another, submitting fully to the Will of God. 

On "ministering" and "evangalism" - Take great care to not think or speak of anyone as if they are a "notch" on your evangalistic belt, either directly or in subtle indirect forms.  This is a slip into the abyss.  It has to do with the demenour and the way you share things, perceive things, and ways in which you "share testimony."  Take care lest your foot slip on that rock . . .   You do not need to "advertise."  Just let the Holy Spirit work in and Through you, which is oft time quietly and gently.  Beloved, there is a time to proclaim loudly from the roof-tops and a time to remain quiet...