
A commonly loved ingredient is low-def 2D graphics. Speaking of basing on existing IP, and low-def 2D, FAUCET's anyone?
Anyway, once your project starts showing more than potential (proper gameplay videos or perhaps something playable), I'd suggest showing it to , and other similar indie-friendly sites.
Honestly, there are loads and loads of guides online which give you advice on making it as an indie, no reason for me to repost what they've said. Read them.