A 2:1 system is pretty darn easy tio set-up and very effectivve.  Simply attach a pulley with a carabiner to the boat end and run a line from the anchor through the pulley and retrun to shore.  As you pull from shore, the anchor moves creating the mechanical advantage.  Your pulling power is matched by the anchor.

The main disadvantage of this system is it takes twice as much rope as other systems.  Heres a nice article on this technique: 2:1 MA.

There are quite a variety of mechanical advantage systems to choose from providing different levels of pulling advantage.  The common ones are:

• 2:1 (C-Drag)
• 3:1 (Z-Drag)
• 4:1 (Piggyback System)

It's a very good safety practice to estimate the load at the anchor point and the object you are pulling to ensure your rope strength exceeds that load.  Another good practicce is placing a weight (damper) a few feet from the object you are pulling.  If the grab loop handle snaps, the damper will provide a drag for the rope and carabiner to prevent it from flying back at the pullers.  Speaking of the pullers, they should be wearing theor PFDs and helmets.  Finally, a racheting system can be quite handy.  This is easily constructed by attaching a Prusik line to the main line and attaching the other end to the anchor.  If you need to let go, this brake line will stop the line from completely paying out and acts as a line capture device.

Vector pulls in mechanical advantage systems is very similar to those for anchors: Anchor Friction and Vector Pull.  An additional consideration is maintaining nearly inline pulls in the mechanical advantage set-up to maximize the pull factor.  Friction can greatly reduce mechanical advantage when carabineers or worse yet rope knots are used.  Both bend the rope very tightly decreasing rope strength and introducing serious friction and heat.