Inspiration
Base your LEGO off of an existing robot from popular culture. Look at robots from classic science fiction series such as "Lost in Space" or "Doctor Who." These robots can resemble humans or look blockier. The blockier robots will be easier to create with LEGOs.
Design
Design your robot on paper first. Rather than attempting to pick from a box of LEGO pieces, sketch out your design and write down the pieces you need. LEGO retailers both online and off sell individual LEGO bricks that will match your design.
Movement
Use the LEGO Mindstorm and Power Functions series to give the robot the ability to move and detect movement. Combine these sets with traditional LEGOs to create a hybrid design that takes into account both form and function.
Competition
Build robot vehicles to compete against robots built by your friends. Allow each person to use the same selection of parts from the LEGO Mindstorm series and have your robots battle or race when complete to see who builds the better bot.
Expansion
Expand your robot to include more than just LEGO bricks. Re-purpose LEGO railings into metal handles for the robot or take the propeller pieces from a LEGO helicopter and attach it to your robot's back.
Mecha
Start with a LEGO minifigure and build a robot body around him. Fans of anime robots such as those seen in the Gundam series can create these robot suits with a miniature pilot. When building around a minifigure, think of him as the core of your robot. If he is in the enter of the robot, build a secure torso to fit him into and add arms, legs and a head.
Smoothing Edges
You might notice that your LEGO robot features sharp edges and the telltale bumps of a LEGO creation Use arch LEGO bricks along with LEGO tiles to smooth our your LEGO robot for a more professional design.
Hinges
Incorporate hinges into your LEGO robot design. Rather than having a robot who always remains in a fixed position, using hinges around its shoulders allows for arm movement while hinges on its legs grants movement.