WIRE. It is very hard to create a convincing bonsai tree without some use of wire. Wiring is essential to steer branches and trunks in the direction you want, to shape the finer foliage and twigs into mature and pleasing shapes, and to pull down branches that rise up in a 'young tree' image. Initially aluminium wire is fine for all your trees, in time you may wish to invest in copper wire for pines and junipers as it does a much better job in the long term