1. Switzerland has two processes for obtaining Swiss citizenship. Ordinary (or regular) naturalization is the one most people go through; facilitated (or simplified) naturalization is a shorter and less complicated process usually open to the foreign spouses and children of Swiss citizens. On February 12th the Swiss will vote on whether third generation foreigners should be allowed facilitated naturalization. According to official statistics just under a quarter of the 40,689 naturalizations in 2015 were facilitated.
2. There's more than one set of requirements. To obtain regular naturalization a foreigner must meet the requirements laid out by three levels of government: the commune, the canton and the Confederation. Federal rules are straightforward, to a point: the applicant must have lived in Switzerland for 12 years (less if you spent your adolescence here), abide by Swiss law and order, pose no threat to the country, be familiar with Swiss customs and (here's where it gets subjective) be well integrated. It's usually down to the cantons and communes to tell federal authorities how integrated they think an applicant is.
3. How long you've lived in your canton is a big factor. You may have lived 12 years in Switzerland but how long have you lived in your current place of residence? Don't expect to move canton (or even commune) and then apply for citizenship – every canton has its own rules on this but all expect you to have lived in the area for a certain length of time. While cantons including Geneva and Bern only require two years' residency, some require much longer, with St Gallen stipulating eight years and Uri a whopping ten uninterrupted years' residency. (Check your canton's requirements here)
4. Cantonal and communal rules vary considerably. Each canton has different requirements (look up yours here), usually centring around how integrated you are in the community you live in. Do you speak the local language to a decent level (and could you pass a test to prove it)? Do you have Swiss friends and work colleagues who deem you part of the community? Do you know a thing or two about the local area? Are you down with Swiss traditions, politics and history? Are you financially solvent?
5. Local residents can have a say. Most cantons and/or communes require you to face an interview to prove your integration and knowledge of Switzerland where you could be quizzed on anything from the number of lakes in your canton to which days are public holidays and the names of local traditions and festivals. In some cases a communal residents' committee gathers to vote on your application, so it pays to keep in with the locals – famously, a Dutch woman was recently turned down by her community for campaigning against cowbells.
6. It takes a while. The length of the process varies depending on where you live, but expect several years. The canton of Vaud quotes two and a half years as a ballpark. And don't think you can move during the process or you may end up having to start all over again.
7. It can be costly. Since there are three levels of authority, there are three different fees to pay. While the Confederation only requires 50-150 francs, costs set out by the cantons and communes can be much higher. The canton of Vaud requires 350 francs and Zurich 500 francs, but others demand far more. Geneva's basic rate for an adult application is 920 francs, but it goes up the more you earn. If your salary is over 120,000 francs you're looking at a 3,680 franc fee – and that's just for the canton. You've still got to add the commune's fees – and all this with the chance that you could be turned down, as one long-term American resident was in 2014.
8. Your likelihood of success may depend on where you live. According to the Tages Anzeiger Western Switzerland is more generous with naturalizations than elsewhere. Official statistics show that Zurich naturalized the most people in 2015 (9,607), but it also has the biggest population, of 1.5 million. The canton of Geneva, population nearly half a million, naturalized 6,093 people last year, despite having a third of the population of Zurich and half the population of Bern, where only 2,587 people obtained citizenship.