Am I a newbie?
certainly not to making people laugh...but to writing jokes definitely,
Im reading a book about writing humour etc and have started writing jokes which is fun, but am wondering....
what do I do to improve my joke writing ?
id like to do standup eventually, would be a great challenge I think.
thanks 
Hello!
This is the right forum for opportunities, just browse the old threads.
Why not post something that you have written on the critique board for people to comment on and see how it could be improved?
I guess think about what you find funniest personally -think of the jokes that have made you laugh the most and then try and work out why they makes you laugh so much.
A good tip I hear/read a lot is that the element of surprise is especially funny, i.e. taking a joke in a completely different direction to the one the audience expects.
Hope that helps!
Exaggeration is always good and don't always go with the obvious.
As well as the things others have aloready mentioned, especially analyzing jokes that make you and the audience laugh, by far the best book I've come across about writing jokes themselves (rather than books that talk about sitcoms) is The Serious Guide to Joke Writing by Sally Holloway.