Go Multi-Classed
My suggestion is to take something unusual by your normal playing standards for race, and then go for a multi-classed character (even split on levels).
I have yet to be involved in a game that had a Gnome character, and Halflings are probably nearly as uncommon as well. Dwarves are another race I do not see very often either. Taking one of those races will give you you a concrete way to avoid duplicating the character archtypes chosen by the other players.
As for the Even Split Multi-Classing, doing that sort of thing is a guaranteed way to fill a role in the party. This becomes even more true when you focus on aspects of your character that other PC's have not focused on.
Example: Lets say you take a Dwarven Fighter / Cleric. Lets also say that the Fighter is a High Str & High Damage out-put type, and that the Cleric uses a great deal of Buff spells. Then why not make a High AC / HP your fighter focus and select a great deal of summoning or buffing spells for your Cleric?
Beyond the previous bits mentioned above, I do not have any other advice, except to do what you can to enhance your enjoyment of the game.
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