Hello everyone i am new To coding plus untiy3d and want to make a 3d game till next year october,2017 so please suggest me what to do first as i am really confused from where to start with!..Thank you in advance… 
Great question.
So lemme tell you what I do :
#1 Think of a theme
What do YOU want to see made.
A platformer that’s a shooter?
Be unique
But at the same time, do something simple that you think you can do, don’t do a project that you know is gonna be long and stressful
#2 Reseach
I personally am making a game that didn’t happen in modern day, My gosh I have to do research Even if it’s fiction, Research how to do stuff that YOU want to see
#3 Never Give Up
I gotta say, I presume you’re new, it states on your profile that you joined on the day of you making this post. So lemme tell you this :
First, This is a form where people will help you, but not give you a full game.
Second, Never Give up, I can’t tell you how many people I was Looking forward to playing their game, then they disbanded on the way.
I wish you luck, here’s a tip if you need game ideas :
Carry around a notepad,
Every day, something happens, even if you watch YouTube videos all day. Whatever happens, No matter what, think to yourself “Would this be a good game”
I personally do this, and I’m running out of space.
Good Luck!
Programming is surprisingly easy to pick up. Just stick with one language and learn it well. There are copious amounts of information about anything you would want to know. Forums are a good ‘safety net’ for when you get stuck, but don’t abuse them to where you don’t want to learn/figure anything out on your own. Watch some tutorials, maybe take a few free online courses and you’ll be set. In the age of the world wide web, everything is at your fingertips. Never forget that.
Pick a goal and break that goal down into simpler goals. Keep doing this until you have a bunch of easy problems. Then start figuring out how to program them into your ‘game’. Good luck. I hope you see your future projects through.