First is graph paper. Any old kind will do. I personally like reinforced filler paper, two sided, which seems to hold up a little better to my doodles and drawings. Double sided gives a chance to use back and front of a single notebook page which opens the view to the imagination. [ 4/sq/inch on front and 5 sq/inch on back ]
Second is "square and circles". [The square = males, the circle = female.] This gives a way to draw a number of generations on the same page and connect the dots. See my blog GE-NE-AL-O-GY 101 for a discussion of this method.
Third is a chronology. By know you must recognize that a detailed chronology is paramount in the tree climbing adventure. The figures show my chronology (in years) placed along the sides of the pages. This can be done in all sorts of intervals. This gives a "time line" to the family tree.
Forth is a coding mechanism. This allows one to give each individual a distinct place in the tree, and hopefully allow one not to get confused along the branches. My coding method is simple and flexible, using the alphabet and numbers. [The coding methods have been discussed in several of my blogs.]
Finally, I like colors. A color code will give a visual picture that can be followed page after page of the family tree. Each major branch is given its own color code, so that as the generations increase, they can be followed page by page. This especially helpful when those folks married 1st cousins!
The drawings shown are done with the graph paper turned side ways. This will also give more room to place the family branch.
Family trees...the leaves will grow and the branches get broader.