You just missed Kissin. He was at the Barbican last week.
If you check out the concert halls near you, or where you are willing to travel to, they will put you on a mailing list for their seasons brochures, then it is relatively to simple to buy the tickets from their box office.
You could also try any websites of the artists you really want to see and see if they have concert schedules. If so you can then go to the box office of the hall they are performing at.
If you have a look at my site for Maxim (link in my sig), I have a concert schedule page with links (where I can find them) to get tickets. I guess other fan sites will do similar.
Good Luck!
Just found this
Kissin tour scheduleHe's at the Proms on Aug 2nd (not sure they should have that up before the Proms are announced...tut, tut!!), and at the Barbican in Sept.