Been doing this for more than 10 years in Switzerland. Here are some options:
1. Miles and more cards from Swiss. I use Amex frequesntly, 9/10 not a problem.
2. Coop shopping
3.
www.Die-weingalerie.ch if you need to buy wines. Often I get 2500 miles / carton. This adds up fast.
4. Hotel booking for non chain hotels through Swiss website.
5. Check out Miles and more shopping promotions if you actually need something that is on sale.
PS: Booking economy with miles and more is a waste of miles and money. They add a big fee. Book business and look for special fares, often at 50% discount (eg 50000 miles return business fares to USA in LX or LH).
For depositing miles for flights with Swiss / Lufthansa, I use another Star Alliance partner that is much easier for keeping the gold level (mainly for Senator Lounges in Europe). I don't fly United to USA but sometimes take other SA partners to Asia.
For USA and other trips I use Delta / Air France / KLM and bank miles with Delta.