@David Violante has some excellent advice!
The flavor ingredient is the absolute most important. Personally, when I taste fruit, vegetables, or flowers if I don't say, "Mmm, that good!" then I don't use it for a dedicated wine. Maybe it can be a secondary flavor in a recipe, maybe it can go in a smoothie.
Also, don't use water for topping up. A similar wine, a similar/same fruit juice, even some teas - anything that won't dilute your wine.
The flavor ingredient is the absolute most important. Personally, when I taste fruit, vegetables, or flowers if I don't say, "Mmm, that good!" then I don't use it for a dedicated wine. Maybe it can be a secondary flavor in a recipe, maybe it can go in a smoothie.
Also, don't use water for topping up. A similar wine, a similar/same fruit juice, even some teas - anything that won't dilute your wine.