Well if it's heavily planted then I'd simply get the plants going and fertilise them and the filter will soon mature with the plant debirs that all to soon accumulates IME. If you can add some established filter media from another tank as this cuts the maturation time down a lot. And if you use Aquasoil you'll have plenty of ammonia from that too!
Like Ed says, chuck lots of plants in the tank from the beginning and turn the filter on. I've used the bacteria ampules and other people have put ammonia in the tank and I haven't seen where it makes a significant difference unless mulm from a mature tank or filter is used. The bacteria levels rise and fall at their pace so the only thing that seems to work is "seeding" from another tank.
Also I dose nutrients and CO2 from day one and I see a distinct improvement. Many prefer to wait a few weeks before commencing the dosing.
I know people who have used a few drops from Homebase household ammonia successfully to get the cycle going. Without any seeding though it takes around 5 weeks to complete, so obviously seeding helps and bacteria from plants will do that although mulm and filter debris is better as there's more bacteria in it.