I never met a sampler that I didn't like. But for a worrisome designer, I would suggest you follow quiltedsunshine's advise and follow a pattern. Go to amazon.com and search "sampler quilt patterns" and 30 pages of a wide selection of patterns shows up. Pick one that appeals to you, select similar fabrics and/or buy a fat qtr bundle of a collection that you love and jump in. Doing it will prove to yourself that a mish mash of fabrics, patterns, and layouts really does come together nicely and the only mistake you can make is over thinking it. Another cautious approach is to join a BOW with a group making a sampler, and audition fabrics with friends one block at a time getting their feedback, input, and recommendations. Best of luck, we are pulling for you!