I am Jewish and an atheist, yet I have a pintele yid and I mean this request sincerely.
I would appreciate suggestions for one doable Jewish practice, prayer, etc. that I might regularly undertake.
By doable, I mean not something like shmiras shabbos.
I appreciate any kind replies.
EDIT Fortunately, I received many outstanding answers, all well-conceived and motivating. I would submit that other than math, everything is opinion based. Math being absolute; either your proof is correct or it isn't. In Judaism itself, just consider the spectrum of interpretation amongst observant Jews, let alone other approaches of non or partially observant Jews. Just consider the discussion as to whether to characterize the site of the Pittsburg massacre a synagogue - how far can you take opinion? The gemara thrives on eilu v'eilu and Rashi v. Tosfos.
To the best of my knowledge, there is no place other than here that I could have received the diverse, unbiased motivations and encouragement. As @ezra put it:
"But one of the most important things you can do (in my opinion) is be proud of being Jewish and be supportive of religious Jews. There are a lot of haters out there. Stand up. Be proud."
In conclusion, the moderators & al. are entitled to their opinion to put my question on hold. But for me, this experience took my participation in Judaism off hold and I am most appreciative.
EDIT2 For the sake of shalom ha'bais, I would like to edit my original post to comply with the guidelines. But I have to be honest and say whatever I do would, in fact, be an artificial contrivance. My only regret is that I have caused anyone consternation. Especially any of the participants who so kindly and generously and warmly extended themselves to hold open the door for me to go to something from nothing. If I haven't already expressed it, please know that I will do my best to implement your suggestions.
That said, I take full responsibility for my post and also for leaving it intact. And I will therefore accept any consequences if I am in violation of any guidelines of conduct and/or decorum at Mi Yodea.