Set a goal to learn how to write, take the time to look into the bookstore and buy a textbook on the Russian language. For example, it would be nice to start with the book that summarizes the rules, which is taught in school from 5th to 9th grades. In this Handbook is collected the majority of the most basic rules of morphology, spelling, syntax, punctuation, and other sections of Russian grammar. Thoroughly studying this tutorial, you will have a lot of questions of spelling.
If you spend every day on the Internet an hour or two, it will be useful whenever there is doubt about the spelling of a word or phrase, check yourself for reference and information portal, the portal to "GRAMOTA.<URL>" at www.gramota.ru. On the main page you can check the word in several dictionaries of the Russian language, and in the "help" section to specify the answer to the specialists of the portal, or to find an earlier question on the topic that interests you.
Typing text in Word documents, in General, you can rely on the built-in spelling and punctuation, however, you should know that the office Suite Microsoft "knows" not all Russian words and rules. Therefore, look for controversial words and punctuation, using dictionaries or portal to "GRAMOTA.<URL>.