Think about the theme of your program. Is there a season or a holiday that you could plan your concert around? Is there a time period that you prefer or a style of song you are interested in? Some examples could include love songs, songs about food, songs about springtime or winter.
Decide what languages you'd like to sing in. Plan to group these songs together into sets. The first set might be three French songs and set two might be German. Or you could decide on a program all in one language - for example, an all Italian or English program. However many languages you choose for your program, remember to keep it to a reasonable length. 60 to 75 minutes is plenty of time for a full-length recital.
Decide what composers you will focus on. If you've chosen to focus on composers from the Romantic period, will you use all famous composers, or mix in a few lesser known writers? If you decide you'd like a variety of styles and time periods, consider ordering the sets in a time sequence from earliest to most contemporary or vice versa.
Once you've picked your songs, be sure the keys of each song work in the order you've chosen. For example, a song in E minor will flow easily into a song in A minor, but going to B flat major will sound too jarring. Pick keys that have a similar number of sharps or flats or are complementary to each other.
Think of the emotional flow of each set in your program. Are the tempos all slow, all fast? Try to choose songs that tell a bigger emotional story. A good example would be a love story; boy meets girl, boy falls in love, falls out of love and eventually they break up. In this scenario, you've included a fast song, an ardent song, and angry song and a sad song.
Choose your final piece carefully. A concert program should end like a good book, with a big bang or final coda.