Preparing a lowball offer to present to a seller

[Karsten Geib]

Firstly, I'm pretty new to the BiggerPockets community and excited to learn about real estate!

My current intent is to find a duplex to live in and rent the other half in order to reduce my monthly rent expenses and eventually start earning income from. So far there is one duplex that has caught my eye, but it seems to be pretty overpriced for the area (by at least $30-40k judging by similar homes sold in the area). It's priced at $248k ($143/sqft) and has been on Trulia/Zillow for 77 days, so I would like to prepare a lowball offer (around $200k which falls in the upper midrange of my budget) to present to the seller if only to get their attention. 

What resources/tips should I look at in order to prepare such an offer? I'm a first time homebuyer and have access to a VA loan, should I speak with my bank right away to see what funding I can afford? Also, I will not be able to physically look at the house for at least the next two months so I can't confirm the state of the property although it appears to be in good condition from the pictures. I'll continue searching through the BP resources, but will appreciate any suggestions on where to start!

Thanks in advance!