Hi!
The key to having a successful twin is to build it light! Not just putting the kit together glueing part A to part B.
Being very cautious to what you use regarding material and equipment and always asking yourself: "Do I really need this part", "Does this part serve any purpouse", Does this part have to be this thick/large/heavy/ etc", "Can I make this part lighter by using any other material" (like glass and carbon). These are the questions I always ask myself when I build my airplanes.

Regards!
Jan K
Sweden