You need to make total profits of a billion, assuming that's still the threshold - I got trade elite ages ago so I have no idea if it's changed since then. As noted above, painite mining in a double painite hotspot will almost certainly be the fastest way to do it these days because your whole selling price is profit. Same for void opals obviously but the painite should be faster.
There's no specific benefit to having trade elite though, or any other Elite rank, other than getting access to founder's world (Shinrarta Dezhra system) which gives a discount on ships and modules and sells every module in the game. At the risk of sounding like one of those tedious 'I remember when all this was fields' bores, it took me getting on for a year to get an Anaconda when I started playing four years ago and I didn't get an Elite rank until after that. Play the game how you like but if you just try to burn your way through everything inside a month, just be aware that your gameplay from that point onwards won't have any kind of structure other than that which you impose on yourself.