Citizens of the Commonwealth of Independent States, Argentina (90 days), Bosnia and Herzegovina (90 days), Brazil (90 days), Chile (90 days), Colombia (90 days), Croatia (3 months, invitation required), Cuba (30 days), Hong Kong (14 days), Israel (90 days), Macedonia (90 days), Montenegro (90 days), Nicaragua (90 days), Peru (90 days), Serbia (30 days, only biometric passports), Thailand (30 days), Turkey (30 days), Venezuela (90 days) all do not need a visa. Anyone else does.
Transit through Moscow Sheremetyevo ,Moscow Domodedovo or Yekaterinburg Koltsovo airports does not require a transit visa, provided the traveller has a confirmed onward flight, remains in the airport for no more than 24 hours and is not in transit to or from Belarus and Kazakhstan (travel to and from these countries use domestic terminals). Passing through St. Petersburg Pulkovo airport requires a transit (or other) visa. Visas can, in some cases, be obtained from consular officers at the airports.
A "visa-free" regime will be introduced for visitors from all nations for the duration of the 2018 FIFA World Cup, which will be held in Russia.
For those unfortunates that require a visa, the complexity of the process depends on the class of visa. Thirty day tourist visas are fairly straightforward to acquire; 90 day (and more) business visas, less so. It is best to start the application process well in advance. While expedited processing is available to those who need visas quickly, it can double the application cost.
Arranging a visa basically involves two steps: 1.) Getting an invitation and 2.) Applying for the visa.
You may arrive at any time on or after the start date of your visa's validity and may depart at any time on or before its expiry date. Normally, an exit visa is included in transit, private visit/homestay, tourist, and business visas so long as the visa is still valid. Other classes, such as student visas, still require a