The uniform makes the guard. If you look sharp, you feel sharp. In a museum or concert hall, a blazer with shirt and tie gives an appearance of civility and says "I'm here to help you". Windbreakers or shirts with SECURITY written on the back and front are best for crowd control since you want them to be noticed. A police-type uniform for officers patrolling a shopping mall is a must to convey the feeling of security. Armed guards, with the exception of bodyguards, should always be in uniform.
In all cases the uniform should be clean and pressed and worn with pride. It represents your job and your responsibilities and goes a long ways towards earning the respect your position deserves. More and more businesses are using uniformed guards who look sharp and attentive, and the traditional "mall cop" look is disappearing. No more slouching, ill-fitting uniforms with the shirttail hanging out, unkempt hair under a crooked hat, and a bored look.
All guards should carry flashlights and two-way radios at a minimum. If they are in a position that might require a use of force or entail arrests, they should carry handcuffs and a baton. Other equipment would include pepper spray, stun guns, body armor (especially if armed), proper uniform and footwear, foul weather gear, and metal detectors. The employer usually furnishes the equipment, except for firearms.
The best place to find security guard equipment is at stores which supply police departments. Many of these can be found on the internet and there is a list in Resources.
The following websites will help in your search for a martial-arts school and equipment. It is important to check a school out thoroughly, and clearly explain your goals, to make sure you can get the right training.
Here is a list of sites selling uniforms: