The following is a quick guide to genealogical research in Austria via the Internet. Your comments and suggestions for improvement of this list will be greatly appreciated.
There are two important considerations before you start researching in "Austria":
Was it really Austria ?
Remember that the Austro-Hungarian Empire of the late 19th century included many areas that are separate countries today. Most people who start researching an immigrant ancestor who is listed on a US census and being " born in Austria" discover that they should be researching in Poland, Ukraine, Romania, the Czech Republic, or Slovenia, etc. You have to start by tracing the Immigration & Naturalization records with the aim of establishing the town or village of origin.
If so, you will probably need to consult the church records.
Keep in mind that there are other valuable local sources such as the provincial or city archives. However they will not do your research for you. Either you go to the archive or you commission a researcher to do it for you.
If you are researching an immigrant ancestor, check these excellent summaries: