Here are some recommendations:
|I do not know how to Play||
Visit our What is Go?  page which gives you links to the right kind of material and some short videos.
|I know the Rules, but nothing else or not a lot more||
For young players mainly: Have you tried Capture Go? It's not a full game of Go, but it's good at getting children quickly familiar with capturing stones (and saving them), which is fundamental to the game. Visit our Capture Go page  to follow this up with a couple of options for playing against a computer.
Why not try the tips  produced for the UK Go Challenge? They're not just tips, but include problems and answers.
At this level some people find that playing against a computer program  on a 9x9 board is helpful. The best of them is Igowin  (Igowin Tutor for iPhone/iPad/iPod) which is a free version of Many Faces of Go .
If you want to play someone else on a 9x9 or 13x13 board and can't find one locally (or they're not available when you'd like them to be) then you could try the GoQuest program  (iPhone/iPad only). This is very nice, connecting to a Go Server (in China we believe) and you'll be playing people at your level of play almost all the time. It also provides a continuous assessment of your level of play - quite addictive really!
We also have a set of 33 problem sheets for you. The problems were produced by Paul Smith for the Cambridge Junior Chess and Go Club, but are suitable for all ages: Index , Level 1 , Level 2  and Level 3 . They're also available in editable format here .
Greg Reid of Queen Anne High School, Dunfermline, Scotland created some problem sheets for his own pupils, but has generously allowed them to be made available for general use. Each sheet provides the answers to the previous sheet (apart from problem 10). They're also available in Microsoft Word format here .
|I've played some 19x19 games (I'm 20-30 kyu)||
You have tried these haven't you? The tips  produced for the UK Go Challenge? They're not just tips, but include problems and answers, and you'll probably get something out them if you go through them a second time!
There's a life and death problem website to visit called GoProblems.Com . It starts off easy, but will trouble the best of our players with the most difficult problems...
Have a look at what we say about Go books for beginners  as there's something for you.
We've also got some tips for self study .
There are many commented games at Neil Moffatt's site  with comments specifically aimed at double-digit kyu and beginning players.
|I just want to get better (I'm 10-20 kyu)||
At this level there are lots of resources, many available free on the Internet, but make sure you've already had a look at those we've mentioned above before going further. We have some recommendations for books for this level , in addition to more books  for all levels of player and you should look at our self study  page.
This linked page  provides a guide to some other resources.
|I want to get better (I'm better than 10 kyu)|