Hi Salima - unfortuantely the statistic of gaining weight is reflective for ALL diets, not just VLCD ones. It's all about the individual and the life long commitment to make changes.
As for tips - drink lots of water, cut down on carbs, sleep more the first 4/5 days and other than that, just stay committed. This diet is a whole lot easier if you have made the committment to be 100%. Good luck and keep posting! x