Overview
Our present protocol (Clough and Bent, 1998; modified from Bechtold et al. 1993) is extremely simple. We have found that the MS salts, hormone, etc. make no difference, that OD of bacteria doesn't make much of a difference, that vacuum doesn't even make much of a difference as long as you have a decent amount of surfactant present. Plant health is still a major factor - healthy fecund plants make a big difference! With this method you should be able to achieve transformation rates above 1% (one transformant for every 100 seed harvested from Agrobacterium-treated plants).
Details
Details of this protocol, Simplified Arabidopsis Transformation Protocol, are located on a web site other than Biocompare Protocols.