If so, what do I do to achieve this?
no, it’s not possible to get a 10 score with your first games but (unlike most game dev sims) it is possible to get a good score (7-8, rarely a 9 thrown in) for your first game in GDT.
thats why game dev is so unique! 
because of that time period, games werent to graghical or anything yet so it wasnt to hard to make it in the game bissnuss back then, now it takes a lot of time and money unlike all other game dev sims, this one stays true to the time zone, etc.