dear aspirant,

first prepare well as your best don't worry about the marks,its depand on your preparation you score more than 500 definetly you get  good rank and good government collegeas you belong to obc category also the cuttoff marks we can't predict so try to score more than 500 .hope you will get best college

all the best

thank you.

Hii

The exact marks which would surely give you a seat is not easy to predict. The cutoff varies every year and depends on different factors like difficulty level of the paper, no. of students etc. 
I can provide you with the previous year statistics so that you can get a rough idea of how the trend goes.
First of all if you are a domicile of Andhra Pradesh then you have 85% state quota there. This would mean if not through AIQ councelling, then you can get a seat through state councelling in Andhra Pradesh.
Now here is the last year cutoff (last score admitted) of govt colleges in Andhra Pradesh for OBC category -

• Andhra Medical College, vishakhapatnm - 562 marks (rank 5414)
• Kurnool Medical college - 543 marks ( rank 8917)
• Guntur Medical College - 548 marks (rank 7959)
• Siddhartha Medical  College, vijayawada - 543 marks (rank 8900)
• Rangaraya medical College, kakinada - 541 marks ( rank 9302)
• ACSR govt Medical College, Nellore - 541 marks ( rank 9465)
• SVIMS medical college for women, Tirupati - 540 marks ( rank 9571)
• Sri Venkateswara Medical College, Tirupati - 544 Marks ( rank 8673)
• Government medical College, anantapur - 539 Marks ( Rank 9827)
• Rajiv Gandhi Institute of medical science, Kadapa - 540 marks (rank 9514)
• Rajiv Gandhi Institute of medical science, Srikakulam - 540 Marks ( rank 9694)
• Rajiv Gandhi Institute of medical science, Ongole - 539 Marks ( rank 9862)

So, with this list, we can conclude that scoring around 560 and above can be a safe score. I would suggest you to keep a higher target so that you get the best of what you dream. 

Hope this helps
All The Best!