How do I start?

Hardware

Let's do this! At the very least you're going to need three simple pieces of equipment:

RTL-SDR stick. Antenna Laptop

Presumably already have a laptop, or at least a computer. You can use any sort of computer with enough guts, but portability really helps when you want to take your setup somewhere. I strongly recommend this. Think of it like stargazing. You might be able to see things decently from your back yard, but if you move out of town things will improve greatly. In the case of some projects, moving to the roof might be enough. Either way, portability is good. Make sure you have free USB ports. I would also recommend a powered USB extension cable to help move your RTL-SDR away from your computer. This will help cut down on RF noise given off by your computer.

I recommend this stick. It works great (24-1766MHz) and comes with a workable antenna. The pictures above are of mine, which should be the same model. (I coated mine in foil tape to cut down on interference). One thing to note is that this model has a MCX connector, which is small and uncommon. You can might want to consider finding a model with a larger connector (such as this) if you want to avoid having to build or buy an adapter down the road should you decide to build your own antennas.

If you want more accessories or would like to geek out about other options, check out this excellent resource.

Software

There are a many options when it comes to software for RTL-SDR. I am partial to HDSDR, but many other users use SDR#. They each have their strengths and weaknesses. My tutorials will generally involve HDSDR, but be aware that SDR# is an option. We may use it in future tutorials for its plugin abilities. For now we'll just need these two pieces of software:

Download and install both programs. I recommend creating a folder where you install all your software and keep all your SDR bits.

HDSDR isn't going to be happy until it can recognize your RTL stick. You're going to need Zadig to properly set up your USB connection to the RTL stick. Follow these instructions to setup this up with Zadig. I've had this be troubling a few times, but stick with it and follow the instructions. Once you've got it going, make sure your RTL stick is plugged in and try opening HDSDR. If you don't get a pop-up complaining about a lack of RTLSDR device you've done it right!