Investigating the history of your house is a really interesting project. You can find out who lived there before you and why the house is laid out in the way it is (this can often be helpful if you are making alterations). If you have the original deeds to your house then you are off to a good start: they should give you lots of useful information about when it was built and who has owned it since.
When was your house built?
Ordnance Survey maps will give you an idea of when your house was built. For South Oxford 1:2,500 scale maps were drawn up in 1878, 1900, 1921 and 1939 and for Cold Harbour in 1878, 1900, 1921 and 1938. You can access them on computers on the top floor of the Westgate Library and at the Oxfordshire History Centre (OHC) (though note that if you want to take electronic copies, you have to pay at OHC whereas it is free at the Westgate). Original estate maps (such as of the Grandpont estate) are also available at OHC.
Who built your house?
If your house was built after 1875 then the original plans for it should be on microfiche at OHC, in their archive of City Engineers’ Deposited Building Plans. These plans should tell you the original layout of the house, the builder, the architect (often the same person) and sometimes the original owner. Here’s an example, of City Engineers’ Deposited Building Plans for 43-57 Marlborough Road. Later plans, up to about 1920, both of new houses and of alterations to existing ones, may also be in the same archive. Between about 1920 and 1970 the City Engineers’ Deposited Building Plans have not been copied onto microfiche but the originals may be in the City Council Planning Department and you can ask to see them. From about 1970 onwards, plans and other documents associated with planning applications should be available via the City Council’s planning website.
Who lived in your house?
The first place to look is in the Oxford street directories which were published every year from 1850 until 1974 by companies including Kelly’s, Shrimpton’s, Valter’s and Webster’s. They are available at OHC. Houses, each with the name of the head of the household, are listed under the relevant street name, which are listed alphabetically. Here's an example of the sort of listing that they give.
Once you have found out who was living in your house via the street directories, you can find out a lot more information about families via the census. Census returns, every 10 years from 1841 to 1911, are searcheable by person’s name via www.ancestry.co.uk and www.findmypast.co.uk. These are subscription services but if you go to the Westgate Library or OHC you can access them on their computers for free. These websites also give access to parish registers (baptisms, marriages and burials); registers of births, marriages and deaths; wills and probate records; and to other archives like trans-Atlantic passenger lists and railway employment records, which are very useful if a former occupant of your house worked on the railway.
You can also look for people who lived in your house on the electoral registers, which have been published every year since the mid-1830s (except for during the two World Wars) and which are available at OHC and, increasingly, via www.ancestry.co.uk and www.findmypast.co.uk. You might also find the occupants of your house listed in telephone directories which are also available at OHC and if you’re lucky they might be mentioned in Jackson’s Oxford Journal, 19th-century editions of which have been digitised and are searcheable from computers on the top floor of the Westgate Library and at OHC. If you have an Oxfordshire County Council library card you can also access this archive from home. Other local newspapers - Oxford Journal Illustrated, The Oxford Times and Oxford Mail - are available on microfiche at OHC.
If it was built before 1910 your house should appear in the 1910 Finance Act valuation books and on the associated maps, which are available at OHC. These will tell you who owned it and who was living in it at the time, as well as how much the rentable value was, and other interesting information. Some of these maps and books have been digitised and are available via pictureoxon.
Here is an example of a house history, written by Liz Woolley in 2009 for 53 Marlborough Road, and here's one written by Anne Kiltie in 2010 for a property in Chilswell Road. Anne also carried out a survey of previous occupants of the house.