I think a macro would be your greatest ally here.

Depends on your platform (you're on PC or console?), a macro to:

a) Pull Target
b) Mark target as 1

would be very good.

I use:

/ac Tomahawk
/mk 1

This macro would instantly target your Tomahawk target to have the mark, instantaneously decreasing your marking time before pull significantly and thus allowing you to have the initial pull. Plus, if you are off GCD, the macro would also mark your target as 1.

I only use this for marking ever. It works all the time.

Before your target dies, quickly change (or tab) to another enemy and shoot that macro to mark it, giving the DPS the next thing to smash and kill, resulting in easier agro management and happy times.