I get a lot of questions about materials, and could share a long list of tools, supplies and brands I love. But I’d like to focus on the things I use most frequently in this post -- the supplies I am constantly coming back to in my art process, and buying again and again for their undeniable utility and quality.
Tube vs. pan sets: I prefer the pan type watercolors because they are less messy, compact, and all around more transportable with a built-in mixing tray that is the back side of the paint case. I use 'half pans' which are the little squares of concentrated watercolor paint.
I frequently use the brands, Winsor & Newton, Sennelier, which both make beautiful, rich watercolors. The pans are set up so that you can replace specific paints, allowing you to really customize your palette, and replace just the hues you use instead of buying new whole sets all over again. I go through canary yellow and hunter green half pans 5 times faster than my blues, and I love unwrapping a new color to swap it out with an empty half pan.
My favorite introductory watercolor kit is the German made Angora kit. I recommend this kit for anyone getting into watercolor, as they provide quality pans of color, and a nice variety of hues. They're affordable, and come in three sizes (14-32 colors)
There is a long tradition of making paints out of elements in our natural world. Currently, there are select brands that specialize in crafting pigments that sell their paints in limited quantities. The high quality handmade paint brands that I love are Case For Making and Greenleaf & Blueberry. Both of these producers produce distinct, natural pigments that are wonderful to paint with, and offer their paints in half pans. I have a travel size watercolor kit and store my handmade watercolors in it, and love the way they perform!
For the kind of detail work and average scale of my compositions, I most often use a series of round brushes ranging from 0-6, and a mix of acrylic and natural hair tips. The larger the number, the larger the brush. If you're building a set for yourself, I recommend skipping a size. Invest in brush sizes 1-3-5, or a 0-2-4-6 for variety, and spend about $6-12.00 each for your brushes- this will land you with a quality product that will perform well and last years if you clean them properly. (Cleaning is simple, wash your brush tips with water after each use). For a super durable acrylic brush, that performs well and is really affordable, check out WN University Brushes or Princeton Brushes (both available on my website). For a natural hair brush that is super smooth for line work and holds its point extremely well, try a Sable round brush.
For watercolor artwork I like a pen that doesn't bleed with exposure to watercolor so I reach for a permanent, archival ink pen. As original art goes, using pens that don't fade with time is a no-brainer, and true black is what I look for in a great permanent ink pen. My favorite is the Copic Multiliner SP, because you can replace the ink cartridge, and they are a very deep black. Microns are also a standby, and ubiquitous in art stores, but they don't last as long, and Staedtler is nice for its metal tip.
Most of the time, I use at least a 90-140 lb cold-pressed watercolor paper. Cold pressed means there's a bit of tooth to the surface, as opposed to hot press, which is a very smooth feel (copy paper is hot press). I prefer the type of cold-press paper that is not extremely textured or rough because I like to get a clean, straight pen line. I consistently buy Fabiano brand because of its minimally textured surface, and because it's a good quality for the price. The higher the weight, the thicker the paper and with it, the ability to absorb moisture. Generally, the thicker the paper, the less your piece will warp, but this should not stop you from using thinner watercolor paper, because you can just stack several heavy books on top of your finished piece and any even lighter weight papers will flatten out just fine.
With all supplies, a little experimentation and an open mind goes a long way when it comes to finding your favorite tools.