How a board works
Every piece of work is a card, and every card sits in exactly one column. Work moves in one direction as it progresses. That is the whole mechanism, and its usefulness comes from what it makes impossible to hide: with the board in front of you, you cannot claim four things are nearly done while eleven cards sit in Doing.
Write cards as outcomes rather than activities. 'Draft the pricing section' can be finished; 'pricing' cannot, and will sit in Doing forever slowly becoming furniture. If a card has been in the middle column for two weeks, it is almost always too big — split it into pieces that can each cross the board in a day or two.
Limit work in progress
The single change that makes a kanban board more than a pretty to-do list is capping how many cards may sit in Doing at once. Pick a number — for personal work, two or three — and honour it: when Doing is full and you want to start something new, you have to finish or explicitly park something first.
That constraint is uncomfortable, which is the point. Starting is free and finishing is expensive, so unconstrained boards fill up with half-done work that has cost you all the context-switching and delivered none of the value. A tight limit converts a pile of things in flight into a queue of things completed, and it usually makes the whole board move faster even though it feels like slowing down.
When to add columns
Add a column when work genuinely waits in a distinct state that you keep having to remember — Blocked, In Review, Waiting on client. Those columns earn their place because they make a real delay visible instead of hiding it inside Doing.
Do not add columns for kinds of work, priorities or people; that is what a card's text or a separate board is for, and boards with eleven columns stop being scannable, which was the only reason to use a board. If your work has genuinely different stages for different types of item, two boards beat one wide one.
Kanban or a to-do list?
A list is better when the work is a set of small, unrelated, one-sitting tasks — errands, a shopping list, a checklist. A board earns its overhead when items take longer than a sitting, pass through stages, or can get stuck waiting on someone else. That is when seeing the state of everything at once starts to pay for the extra ceremony.
Kanban answers 'what is the state of everything?' If your question is instead 'what should I do first?', prioritize with an Eisenhower matrix and then put the survivors on the board. The two work well back to back, and both save to the same canvas here.