As to what pieces to buy, I love this sweater. It's neutral but exciting at the same time.
River Island | River Island Knit Textured Jumper at ASOS
Here are other knitwear options:
ASOS | ASOS Block Stripe Jumper at ASOS
River Island | River Island Fairisle Collar Jumper at ASOS
ASOS | ASOS Cable Detail Crew Neck Jumper at ASOS