package MyPkg;

# use a pragma

use vars qw( $foo @bar %baz );

# or declare the full path

$MyPkg::foo = "this";
@MyPkg::bar = qw(that);
%MyPkg::baz = ( the => 'other' );

# or declare the variables before 'use strict'

$foo = "a string";
@bar = qw( an array );
%baz = ( a => 'hash' );

use strict;
...