Same general advice as for level 1:
- If your garden is not yet public, invest in a Feeding Table and put vegetables on it, to attract your busy friends more often and speed the acquisition of those important diamonds. Visit and water at least one plant in someone's garden every time you collect your "3-hourly" gold, to try to spot another crittur. And remember your "twice daily" free Mushroom Game tokens: you don't get more until 12 hours after you collected the last batch; maybe you should write each collection time in your diary so as to get back as soon as the next batch is there.
Progress to level 3 requires the harvesting of
- one Carmena Uniflora and
- two different-coloured Bellis Lycaena both different from the first colour you harvested for level 1. If one turns out to be the same colour, you can change it before harvesting; but a few levels later you will need to have harvested two of each colour, so maybe you need not change this one.
You can also plant a Thornbloom Herb for Herbalism experiments and attracting and/or repelling wildlife. It is the best herb for attracting the Lop Eared Bunny (worth 4 diamonds), but that rabbit needs Mixed Vegetables and is deterred by all other fragrant or flowering herbs, so, as soon as a Thornbloom starts flowering, harvest any Nestflowers (when they're ready) and don't plant more of them.
If you have spare pots, start another Carmena or Bellis, because you will need to have harvested seven of each by level 6.