First of all, you will need to obtain the appropriate Argentinean visa. Visit the Argentinean embassy in the country of your residence, take care of the necessary prerequisites and apply for the visa. You may have to make more than one trips to the embassy before you can apply for the visa. Since you plan on moving to Buenos Aires, you would need to obtain a permanent visa which would take longer than obtaining a visit visa so make sure that you plan ahead of time.
Purchase health insurance applicable to expatriates while you are in your own country. This will make it much easier for you to manage any health related expenses that you may come across during your stay in Buenos Aires.
Research some of the various neighbourhoods in Buenos Aires ahead of time. You can use internet for this purpose. Choose the neighbourhood which would best suit your needs. If you are more interested in vibrant city life, Puerto Madero, Retiro, Recoleta and Barrio Norte are some of the possible options. However, if you are interested in living in an old neighbourhood, consider doing some research on San Telmo or La Boca.
Depending on the amount of money that you plan to spend in terms of monthly house rent, find an appropriate apartment unit or house. Again, make use of the various online websites where you can find rental and property listings. Another option is to find a temporary residence upon your arrival in Buenos Aires and then take some time to find an appropriate house or apartment unit.
Learning the proper language is of pivotal importance. Portuguese and Spanish are the two widely spoken languages in Argentina. Learn either or both of these languages. This will help you adapt to the conditions more easily and you will also be able to make some friends in the neighbourhood more quickly.