Minimum land diameter for a plated through hole according to IPC-2221, the drill size and plane clearance, or a check of the worst-case annular ring of a pad you already have.
Minimum land. IPC-2221 section 9.1.1: Land = a + 2b + c, where a is the maximum finished hole diameter, b the minimum annular ring (0.050 mm on external layers and 0.025 mm on internal layers in IPC-2221) and c the minimum fabrication allowance for the producibility level: 0.40 mm (level A), 0.25 mm (level B) or 0.20 mm (level C).
Worst case. The fabrication allowance accounts for drill wander and layer registration. The worst-case annular ring of an existing pad is (pad − hole − c)/2.
Drill and antipad. The drill is the finished hole plus the plating allowance, typically 0.05 to 0.15 mm. The antipad (clearance in planes the via does not connect to) is the drill diameter plus twice the clearance.
Your manufacturer's own minimums (often 0.1 to 0.15 mm annular ring) override these values when they are larger.
The ring of copper left around a drilled hole on a pad. If drilling or registration error shifts the hole too far, the ring breaks and the connection to the trace can be weakened or lost.
Level A for general boards from any shop, level B for most standard prototypes, level C only when you know the manufacturer can hold tight registration.
Minimum spacing between conductors for a voltage, from the IPC-2221C table for all board locations.
Width a trace needs for a current, or the current a trace can carry, with IPC-2152 and IPC-2221.
Impedance of an outer-layer trace over a plane, with solder mask or embedded, and width for a target impedance.
Impedance of an inner-layer trace between two planes, symmetric or offset, and width for a target.
Differential, odd, even and common-mode impedance of edge-coupled microstrip and stripline pairs.
Impedance of a coplanar waveguide, with or without a ground plane underneath (grounded CPW).