Reddit mentions of Practical Plant Identification: Including a Key to Native and Cultivated Flowering Plants Families in North Temperate Regions

Like others have said, learning what characteristics plant families have makes plant I.D. so much easier. If this is something you really want to learn, I'd recommend a book like Wendy B. Zomlefer's Guide to Flowering Plants or Practical Plant Identification by James Cullen. Both of those should give you a rundown on common plant family characteristics and help you narrow it down at least to a family, if not a genus. Being able to accurately I.D. plants quickly is mostly practise, though; the more you do it, the easier it gets.

Though, because you don't think it's a native plant, once you have a rough idea of what it is, you can look at ornamental plants that will grow in your zone.