Bases

I usually use an X-Acto knife or a file to round off the edges.

Then glue the crewmen to the base.

AA gun crews.

Having the crew separate allows them to take casualties or be in a moving position.

Bases later get painted with the figures.  Sometimes.

Making Bases

I use Evergreen Plastic Tile for bases.

Three long and two deep is usually enough for one soldier in 1/72nd scale.  Just bend at the line and you don't have to measure or cut.

That gives you a long strip.

Count two squares and bend again.

Bend back the other direction and the fall into tiny rectangles.

Bases

Getting the crew ready.

I make up a lot of troop bases ahead of time.

Gun bases with holes plugged.

Apply glue to the underside and then stick the rod in and cut it off.  

Same with the flag.