Most of mine are actually 10%. It is tough, but I squeeze in 3-4 trades a week. I used to enter Monday's but now I find the pricing is better for my strategy between 10am-11am Tuesday mornings for that Friday expiry.
I have the discipline to not trade when I don't find a trade that week to fit my criteria. Also, the more expensive the stock (pure dollars) the better premium and R/R.
For example NFLX is ~$330 and the strikes increment in $5, but GOOG is ~$1,125 and increments in $5 too.
So all else equal, the GOOG options for a given single-strike spread will be worth more for the same "fixed-risk" due to the spread distance.
This helps with my R/R.
Its not perfect by any means, I have lost, but I am net up.
Also, at a high level, if you're trading four (4) ~4:1 R/R trades of equal dollar-size, one trade can blow up a week and you'll be NET 0.
Combine that with a "probability" of sub 15% and you've have positive EV.
Oh, but that probability is a tricky one.