needing advice for negotiating purchases of off-market properties

[Devin Roberts]

hi there, i am a rookie home investor who has been looking for off-market properties to purchase. i have never bought a home before but i have doing some door knocking and have got some leads on properties that are selling off-market. one house has been sitting vacant for 5 years, and is finally getting out of probate. they told me they're getting the deed this week. i called the homeowner and they have a few people interested in purchasing besides me. 

i have never negotiated an off-market deal with a homeowner before, and have absolutely no idea what i'm doing in terms of buying the house. of course, they are going to get the house appraised, and i've been looking at other properties in the neighborhood to help me assess the value. 

biggest thing i want to know is: how i can HELP the homeowner in this process? what could i do FOR THEM that they would find beneficial? they are also 2 years behind on property taxes... is there any way i could help them with that?

what are my next steps? what advice can you give me about how this process works?

do i need to use a real estate agent? can i used  a real estate lawyer instead? what do you recommend?

any and all advice welcome. thanks!