Homebrewing means building your own equipment, from a bagged kit to a circuit you designed yourself. It is the oldest tradition in the hobby and still one of the best ways to learn, because a circuit you have built and debugged stays understood. It is also optional: plenty of good operators never pick up an iron.
The path in
Each step adds a skill: reading instructions, then understanding the circuit, then sourcing parts, then design.
Kits come with the parts, a circuit board and instructions, so the only skills needed are patience and careful soldering. Kits exist for receivers, low-power transmitters, antenna tuners, keyers, test gear and many accessories. Choose one with a clear manual and a good reputation among other builders. If you can find a local club building the same thing, even better.
Repairing and modifying gear teaches you how a circuit works, because you must find out where it has gone wrong. Start with something inexpensive that is already broken.
Building from a published design means finding a schematic in a book, magazine or online, buying the parts and making your own board. Pick a design that others have built successfully and reported on, so the problems you meet are known ones.
Designing your own comes last, once you understand how the parts of a circuit interact. Free simulation software lets you test an idea before building it, but real measurements always have the final say.
Good first projects
Wire antennas and feed lines. A dipole or an end-fed wire is the classic first build, and you can measure how well it works. See The half-wave dipole.
Cables and power leads. DC power leads with an inline fuse, coax jumpers and audio cables teach you soldering and cable strength with little risk.
Simple filters and keyers. Low-power circuits that are easy to test with a multimeter and a receiver.
A dummy load. Useful and satisfying; keep it within its power rating. See Dummy loads.
Habits that save projects
Read the whole manual first, then sort the parts and check each against the list.
Verify values before soldering. A multimeter confirms a resistor's value; the colour code can be misread (see Resistors).
Build in stages and test each: power, then bias, then signal. A fault is far easier to find in one stage than in a finished box. See Troubleshooting.
Take photos as you go and keep notes. You will use them later.
Check your signal. A homemade transmitter must meet the same limits on spurious emissions as a store-bought one, so listen for harmonics or check with a spectrum analyzer.