A good starting point for this answer can be found at http://hubpages.com/hub/Stop-Excessive-Sweating-Naturally where some of their adivces are:
* Drink a lot of water
* Stay Calm
* Cut down your caffeine intake
* Take a cold shower -
* Drink tomato juice
* Avoid alcohol, cigarettes and drugs
* Avoid sugary, spicy and chemically-processed foods
* Wear socks
* Lose some weight
For each of the points, they give a brief explanation of the context for that suggestion. For example, for "Lose some weight", they say "It's a fact that 90% of people facing problems arising from excess sweating are overweight. Cutting down on that extra weight drastically increases your chances of dealing with excess body sweat"
The following sites
list various standard medicinal treatments including:
Note, that if normal antiperspirants do not work, your doctor may advise an antiperspirant that contains aluminium chloride. This is a 'strong' antiperspirant. It is thought to work by blocking the openings of the sweat ducts. It tends to work best in the armpits. However, it may also work for sweating of the palms and soles.
* Oral medications
The anticholinergic drugs, oral propantheline (Pro-banthine®) and oxybutynin (Ditropan®) may reduce sweating, but unfortunately can cause blurred vision, dry mouth, constipation, dizziness and palpitations. They should not be taken by those with glaucoma or urinary retention.
Beta blockers may also be helpful as they block the physical effects of anxiety. They are unsuitable for those with asthma or peripheral vascular disease. Calcium channel blockers, nonsteroidal anti-inflammatory drugs and anxiolytics may also be useful for some subjects.
* Botulinum toxin injections
Botulinum toxin injections into the armpits are increasingly popular as they can reduce or even stop sweating for three to six months.
Botulinum toxin is also effective for the palms and soles, but is not yet licensed in New Zealand for this purpose (June 2008). It may temporarily weaken the small muscles of the hands. Regional or local anaesthesia is desirable in these sites as the injections are painful.
Finally, some complementary treatments can be found here: