[Such is the nature of asking Twilight Sparkle for advice. Getting her to be brief is a major accomplishment.]

Well, there are seventeen different "types" that Pokemon fall into. [Eighteen actually but the whole Fairy thing hasn't been sorted out yet.] Some Pokemon have more than one. Ideally, you'll be wanting to form a party where each of the members has at least one type unique to them, since some types work better or worse against others.

For example, that Pokemon you have there is called a Snorunt, and it's an ice-type. That means it works well against rock, ground, grass, dragon, and flying types, but fares poorly against fighting and fire. The first thing I'd suggest you do is find other Pokemon that can cover those weaknesses. Flying and psychic types do well against fighting, and water, rock, and ground smother fire quite well, for the record.