Before you begin, take into consideration what color your pot is. For example, if it's red (like this one), stay away from pinks. If it's blue, try to incorporate brighter colors (yellow, orange, bright pink, etc.).
Here's a shade planter recipe!
1- 'Sweet Caroline Sweetheart Purple' Potato Vine
1- Plectranthus Variegated (white/light green)
1- 'Colorblaze Sedona' Coleus
1- Apricot Upright Impatien
1- 'Berries & Cream' Nemesia (small purple/white blooms)
3- 4 pack 'Trailing Dark Blue' Lobelia (not in bloom yet, but it is in the pot!)
1- 'Abunda Colossal White' Bacopa
Another note: We love to use shade-loving perennials in pots as well. We use lots of ferns, hostas, heuchera, helleborus, boxwood, holly, hakonechloa (bright yellow, shade grass), etc. You can either leave these perennials in the pots from year to year (remembering to water them throughout the winter), or you can take them out of their pots and use them in your landscape! Double duty!
Most importantly, have fun and don't be afraid to experiment!