Whoa, that's a really broad couple of questions. OK:
First off the best advice I can give you is to invest in what you know and don't get greedy. Stay in your comfort zone - you should be investing in to companies, industries and sectors that you are familiar with. So if AngloGold Ashanti issue a trading statement, you should understand exactly what they are talking about, whether they refer to something from their past or whether it's just technical jargon relating to mining rights or the quality of deposits being poorer than expected etc. And set yourself a pricing goal and stick with it. Always leave something for someone else - this sounds contrary to what trading is about, however greed will get you burnt. You should be looking at the fundamentals of the company, broker consensus estimates and related research, annual reports, SENS announcements, general company news, industry news, looking out for corporate action in the industry (M&A, takeovers, reverse takeovers etc), registering on the company's investor relations website and most certainly determine your own criteria for investment and stick with it, taking all of the above into account.
Regarding the political question. All shares will be affected equally by political issues such as the elections, however those more susceptible will be those already in dire straits and heading south. When politics will affect specific companies is when it is specific politics, such as legislation, competition commissions, policy changes, economic announcements etc. Only then are some industries and companies more affected than others.
And btw, Zuma stepping in to power won't necessarily result in the market plummeting. The market already knows this will happen and prices these factors in long before they actually happen - although if elections go off without a hitch then we may in fact see positive sentiment in the market, not necessarily negative...