Maybe find the easiest BD player you can beat, and get your 10 free items per day.
Free codestones if nothing else. More Neo cred hopefully in the process.
Definitely recommend, as others have, playing a variety of games. Do the best you can manually, even if you only play the games once.
If you do go for the Top Gamer avatar then I'd suggest TheDailyNeopet's tool: here
Checks which games you've already have 'played' and which games are still available to play.
Then personally I'll collect a few of the collectable cards. Mainly ones that interest me.
Fairies, villains, cool art work, etc.
Even multiple of the ones that I consider favorites.
Find it a bit weird you'd be called "suspicious" after 10 months of gaming.
But I suspect the problem is mainly how many games you've actually played vs how many trophies you have.
Would definitely go with playing more for the sake of expanding your high school/Games Played list and not even worry about trophies for quite awhile first.
Oh, and while it's too late now, having at least a Rank 3 trophy from the Games Master Challenge(s) probably would help.
And pretty much any opportunity for a Site Event trophy you can get. Altador Cup when it comes around, GMC, etc.