'NMW should rise dramatically, to a 'living wage', and the low threshold for tax should rise too'
Labour say that they are in favour of a "living wage" but what they say and do is often different. Meanwhile, Osborne increased the minimum wage by about 10% I think. Also under Osborne and the LibDems, the tax threshold has risen substantially and is likely to be increased even more. I doubt Labour would do the same, because their focus is more on benefit increases rather than those in low-paid employment. Isitmebut will have all of the figures to explain it better.
'I am against free schools. I think they cause divisions within local communities in terms of religion/ethnicity discrimination etc. I am however in favour of academically selective grammar schools and independent schools. I would like to see the return of the Assisted Places Scheme.'
If you are against free schools, then in theory you would be better off under labour as they say they are against opening new ones, but they won't close the ones that are already open. Again what they say and what they do are often different as we will find out if we have the misfortune to elect them again. The Tories are in favour of independent schools, but not academic selection or grammar schools. If you want that then UKIP is your bet.
I am in favour of HS2 and generally in favour of increased infrastructure & transport links, and wind power.
They are all in favour of those apart from UKIP which I think has no reversed its polcy on HS2 an is against it and which is against wind power. Some Tory rebels are against wind power, and Cameron was allegedly supposed to have said let's cut the "green crap", but as ever what they say and what they do are often different, and most people believe Cameron is green through and through - he even has a wind turbine on his roof! 
"I support First Buy schemes etc. but (and I don't know much about this) would support schemes to limit people buying up properties and then not living in them"
The Tories support First Buy schemes and Labour probably would do too. Limits to people buying property and not living in them is the sort of thing that Labour generally likes unless it applies to their own homes and the homes of their ex-leaders, bigwigs and nose in the trough luvvies. Conservatives generally believe in freedom, so would generally be against restrictions on this type of thing.
'I am in favour of no cap on immigration providing they have a job in the UK before emigrating'
That is more like a UKIP policy. The other parties cannot place a cap on EU immigration at all. As Farage says, in theory 485 million people have the right to move here if they want to.
So, on the whole, you are a bit of everything. You need to decide which of the issues are the most important for you. Weight them and then decide which party best meets your needs and best matches your views on your core issues and principles.