Apple trees

[jojosapphire]

We currently have 4 apple trees in our garden they were planted by the previous owner. We moved in in August and had apples from all 4 but not sure on varietys the big one is defiantly a cooking apple.
I know the big tree could do with looking at by someone who knows what they are doing but due to an iminent extention cant afford anyone....
So the medium 2 i can reach (sort of) with a ladder but what am i aiming to do to incourage better fruit growth? Oh and the 4th tiny one had 3 green apples last year. The garden is north facing but quite open to the west so get lots of sun in the afternoon in the spring/summer the apples are on the back wall which is south facing.

Thanks in advance....

I'm assuming these are free-standing trees not trained ones (e.g. fans, espaliers?) There is some good advice here:

www.rhs.org.uk/advice/profile?pid=90

Basically:

1. Stand back and have a good look at the tree, ideally with a cuppa.
2. Get rid of any obviously diseased branches.
3. Get rid of any branches that are crossing, as these will rub and cause disease.
4. Get rid of water shoots completely (the springy bits that sprout from the top of the tree)
5. Thin out any areas that are congested - where there are loads of branches that may inhibit the movement of air through the tree. Ideally you want the tree to be a kind of bowl shape so in practice this means getting rid of stuff that's growing in towards the centre.
6. Get rid of anything that is getting in your way.

then

1. Shorten last year's growth on each of the main branches by about 1/3 where branches are already as long as you want them.

It sounds way more complicated than it actually is. Watch a couple of Youtube videos and you'll soon get the hang!

Thank you, will do some research and make a plan!