As it seems you are new to CP's,
First read some of the info here on TF & elsewhere on the net, about the plant you are wanting to get. Make sure you can give the plant the environment it needs (light, temps, humidity, rain/R.O. water, etc.), then look at the picture of nice plants!
Also, go to the library (if you have one) & read up on them. Nothing worse for your self esteem than to go out & kill a plant immediately, because you don't have a clue what you are doing.
As far as condition general info...
You don't want anything blotchy, rotten, or especially with bugs!
Beyond that it is mostly common sense.
Keep in mind that many plants will be in dormancy at this time of year, so the plants may look shabby even though they are healthy.
That's about all I can offer at the moment.
Good Luck