In addition to paint, brushes, and paper, here are a few other things I like to have on hand.

2 cups of water: One to wash off your dirty brush, and one that stays clean so you can mix colors with clean water. You can use any kind of glass jars, but I like to use something heavy that will easily stabilize on my desk — like a reusable glass jar with a lid. Paper Tissues & Old Cotton Cloth: to dry brushes.

Mixing palette For: For mixing colors and curating custom palettes of paint. The while ceramic or proclaim palettes are recommended as they blend paint and usually wash completely clean and don’t stain. Besides you can also consider purchasing leakproof watercolor pallets and the suggested links enclosed:

https://www.amazon.co.uk/dp/B07LG1QHBQ/ref=cm_sw_r_wa_api_fabc_dzE-FbY3GVAHZ
https://www.amazon.co.uk/dp/B07TRKHNW6/ref=cm_sw_r_wa_api_fabc_u8G-FbZ1V9XFQ

White gouache: Traditional watercolorists use the white space of the paper to form white in their paintings, but at times, I like to use white gouache sometimes ( optional)

White/ Gold/ Silver gelly roll pen from Sakura https://www.craypas.com/global/products/18617: gel pens are fun to use for mixed media pieces. Once your watercolor wash is dry, you can draw right on the wash ( optional).

Masking tape: For taping down your paper to keep it taut while painting ( occasionally used).

Towel/Sponge: For blotting off excess water and/or paint from your brush during painting( occasionally used).

Masking fluid: A liquid latex mixture that’s used to keep the paper dry and white over large washes. ( occasionally used)

Pencil + eraser: For sketching beforehand if necessary ( occasionally used).

Kneaded eraser: A special kind of malleable eraser that you can rollover your sketch to gently lift some of the pencils. Kneaded erasers are helpful because if a sketch is too dark, it will show through the paint ( optional).

Hand-held Blow Dryer: For drying layers manually rather than waiting for them to dry naturally.

Archival ink fine liner pen Sakura https://www.craypas.com/global/products/18676 : for fine sketching and mixed-media work. Watercolor and black ink sketches make for a fun combo! Make sure to use archival (aka permanent) ink if you want to sketch first and paint on top, or else the link will reactivate and go blurry ( optional).

Clipboards (varying sizes): For managing multiple pieces at a time. Tape down your paper to the clipboard, paint a layer, and then set it to the side to dry while you work on something else ( occasionally used).

Hope you find this useful. Joyful painting friend!