MOST IMPORTANT - be patient - take your time, dont do it all in one day, easier to make mistakes if you rush it.
Couldn't agree more...
I started with full kits with drilled enclosures - the $30 Landtone ones on Amazon, but I don't know if I would recommend those if you're completely new to this. The nice thing is that they come with everything you need to build the pedal, but the instructions are garbage, and you will get frustrated. The other problem is that the pcbs aren't good quality, so if you do end up having to desolder a component, it's real easy to pull up a trace, and there is a lot of off-board wiring that you'll end up trying to cram in the little 1590B enclosure.
A better choice (if you want to spend the money) is a StewMac kit. The instructions are excellent and the pcbs are better quality, but they don't label the parts, so you'll spend a lot of time trying to read resistor bands. (I highly recommend you invest in a multimeter. You don't need to splurge for a Fluke, but you should get something that will read a resistor and has an audible continuity tester.)
A still better (and much more affordable choice) is to find a pcb on PedalPCB that has a low part count -- something like the Executive Fuzz or something with a similar part count. You should be able to get all of the parts you'll need at Tayda. Just remember that you're going to need more than the listed parts on the build doc. You're also going to need the enclosure (many of which you can get pre-drilled and powder coated), the jacks, the power jack, foot switch, knobs, etc. Just take your time and make sure you have everything before you place the order -- you only want to have to pay for shipping once. Also, make sure you can find all of the parts before you buy the pcb. There are parts in some of these builds that are no longer available, and there is nothing more frustrating than ordering a pcb that you can't find the parts for - especially when you are new to this.
Although not required, you might also want to get a breakout board for the footswitch. Personally I find the switches easy to understand, but I know those 9 pins on a 3pdt switch can be intimidating if you've never done this before. Buying a $1 breakout board can save you a lot of headache for your first builds.
As for soldering -- get a decent soldering iron. You don't have to break the bank to find a decent one, but you'll regret it if you skimp and buy a super cheap one. Ideally, you want one that you can control the temperature and find replacement tips for. For solder, i recommend a 60/40 tin/lead solder -- it's a lot easier to work with than the lead free solder. And if you're new to soldering, practice on something before you build your first pedal. You can buy cheap soldering practice kits on Amazon for $10 to play around with or just practice on a piece of perf board.
And lastly, watch a lot of YouYube videos. There are tons of really good videos on YouTube about building pedals and electronics.
Sorry this post is so long...