Identify all nodes in the circuit:

The wiring connections among circuit elements are termed as “nodes”. In the figure above, circuit elements are illustrated in blue and the wires are green. All the wires which are joined altogether form a single node, despite of the number of elements joined in the node.  The illustration circuit has 3 nodes: one joining V₁ & R₂, one joining R₁, R₂, and I₂, and a final node which joins elements V₁, R₁, & I₂.

Note that dots are only to elucidate electrical connectivity. The node might contain zero, one, or more dots. The number of dots has no connection with the number of nodes in a circuit.