So, you've completed your first project. Hopefully it worked first time, or at least without too much hassle. Your probably wondering "What do I do next?" That's up to you. While it's a good idea to start with a kit, which will lead you through the first steps in electronics, after that it's up to you. If your first project didn't work straight away, it's probably as well to build a few more simple kits before tackling anything else.
You could build more kits to get more confidence, or build magazine projects. It is a good idea to buy a magazine, such as Everyday Practical Electronics or similar. As well as having projects in, it is a good way to gain basic knowledge of theory. They often have good articles especially for beginners - such as their 'Practically Speaking' column (published in every other issue).
You will probably want to learn some theory sooner or later so you can design your own circuits. I know theory can be boring, but even just the bare basics will enable you to design simple circuits - this can be much more satisfying than building a kit, even if the circuit is simpler. Probably the best way to do this is to buy a book or two on basic electronics - resistors, capacitors, transistors etc. You can then go on to more complex stuff when you know the basics. Also see the Data Archive on this site - it contains some pages on component theory, and much more.
That's about all that can be said. Hopefully this section has helped you to some extent at least. Remember that both the Technical Data Archive on this site, and component suppliers catalogues and websites can be good sources of data when designing a circuit. The Data Archive includes pages of basic theory on resistors, capacitors, diodes, transistors etc. and is well worth a look. Also check my links to other electronics sites, as these can be very helpful too.
The following page is a guideline to extending your toolkit, and other useful items of test equipment.