You have a wide choice, and the choice is yours.

Maybe first collect stamps in general, and then see what you like best ?

Postage stamps, being stamps used for prepayment of postage. 

Stamps can be collected by country – well over 200 geographic entities (countries, islands, federations) have issued stamps.

Or by period, for instance before it became a republic, stamps were issued by the Union of South Africa (1910-1961).

Or by another grouping, like British Commonwealth stamps during the reign of King George VI (1937-1952).

Or you can collect stamps of your particular interest, like locomotives on stamps (at least 14 other countries have depicted South African steam locomotives on stamps), or helicopters, or birds, or shells, or rugby on stamps (the first rugby stamp was issued by Rumania in 1944) …  or whatever you fancy.

Some postage stamps were issued for specific purposes, like airmail stamps.  Or parcels, or special speedy delivery. 

Postmarks are often as exciting as stamps ! You can collect postmarks by country, by region, by shape and other features – the options are almost endless.  How many postmarks do you know with place names ending in –fontein ?

Postal history is a term used for used envelopes which show postmarks, postal rates, often postal routes, special treatment such as registered mail, underfranking and the collecting of the postage due, wartime censorship, and even envelopes salvaged from sunken ships or crashed aircraft and trains.

Airmail envelopes marking pioneering air routes are also postal history, as are envelopes recording events such as Antarctic expeditions.

Included in the wide definition of ‘stamp collecting’ is postal stationery, being prepaid postcards, envelopes, registration envelopes and aerograms issued and sold by the post office.  

Offshoots of stamp issues may be sheetlets, and first day covers issued to feature new stamp issues.

Revenue stamps . Stamps issued as receipts for taxes paid are also collectibles, and are displayed in a special section of major stamp shows.

Indeed – the choice is varied, and always exciting …