You would at least need 20 days to plan and prepare the complete  show… assuming the venue and invitation cards have been finalized and  the food/catering has also been taken care of. The preparations for the  show include:
List the people available to dance for the show 
Make a list of all the people who you think will participate. Some  people are but hesitant to dance and might need extra convinving. To  make it more interesting encourage all family members to participate.
Choosing the right song for everyone
This is a very important part that needs to be given due  consideration. You must make the song selection with utmost care… one  aspect is that the song chosen should go well with the person going to  dance for the song, another is that the song selection should not be  monotonous. To make the show lively enough to grab the attention of the  guests during entire time, there must be a variety in the songs. It can  be a mix of slow songs and some peppy numbers, songs describing the  excitement of the bride and groom and may be some emotional songs where  the bride and her mother experience the pangs of separation from each  other, some folk songs dedicated to marriage and bride and some love  songs. To give more life to the show, don’t forget to add some top hindi  dance numbers. The song chosen for the Bride and Groom should not  preferably be a fast number. It should have a special meaning for the  happy couple and should convey to the guests the unique bond they share.
Other ideas to make the show more variable and exciting are, a medley  of songs rather than someone dancing on one full song, a dance parody  that can also be based on a theme, a dandiya dance, a “diya” dance  (carrying battery operated candles), a song sung by some ladies in the  family (this can also include some teasing either for all couples in  your family or for your “samdhi”) or may be a small skit.
The show should be a mix of solo dance performances, kids dance,  couple dances, ladies group dance, girls and boys group dances, couple  dances, and may be one performance where the entire family comes on the  stage.
Dance choreography and practice sessions
If you have the talent, choreograph the dances on your own, else  either take lessons or use an instructional video. If you have trouble  finding a teacher that you like, or if time and money are  considerations, you may want to try learning to dance from an  instructional videotape. Make sure that all the dances have been  choreographed and taught to the people at least 2 days prior to the  show. Since everyone would get time to practice their full performance  during these two days, it would give them more confidence while  performing on the final day.
Each person has his or her own way to dance… you should therefore  keep this in mind while doing the song selection and while  choreographing. The dance steps must go with the dance and with the  dancer.
More attention is required while choreographing the dance for the  bride and groom. You can try to put some special effects for their  dance… “dulhan” entering the stage in a “doli”, etc.
Decide on the right outfit for each song
Selection of right costumes for each performance would add more  perfection to your show. More critical are the group dances where the  dresses should not only go with the dance and the song but its also  required to have some kind of similarity between everyone dancing on the  song… like all pastel colours or all bright colours, everyone wearing  sari in a similar style but a special one different than the ordinanry  style.
Plan the sequence for all the dance numbers
Just be careful that no two similar dances are placed together. The  sequence must be such that the show is a mix of slow and fast numbers  and solo and group performances. The limelight for the day, the dance of  the Bride and the Groom should be placed more towards the end of the  show. The show should end with something like a “Grand Finale” where the  whole family comes together.
Anchor and anchoring script
To add some more charm to the celebration, you can have an anchor  person who would entertain your guests and tell them about the show. You  can either hire a professional or it can be someone among your family  and friends, of course in the latter case you need to prepare the  anchoring script by yourself
.
If you hire an anchor, he must know the sequence of songs and who are  the people dancing on them, in order to prepare the anchoring script
Decoration 
Sangeet decos are done in best possible unique ways to cherish the  ceremony. Sangeet decos could be of various types. They may be wedding  themes based or on personal taste and budget. Traditional decortion  could be made for sangeet celebration. Saneet decos also could  be made  ethnic by using colours like red, orange, bandhni, maroon or purple  drapes with some golden glittering colors. This concept could be carried  for decorating the entire area. Flowers like rose, marigold, orchid,  gerberas could give a special touch to the sangeet decorations. A  traditional theme like long beautiful drapes in rich embroidery and  mirror work could give a special touch to the sangeet celebration.  However, in order to give it a western look, netted drapes and silver  color in place of golden can be used. One can also use flowers like baby  roses, orchid, lily or carnations for western Sangeet decorations.  These days people sometimes prefer to decorate with heart shaped  balloons and nets, which goes with the love based theme.
Music system and lighting effects, DJ
Since the sangeet ceremony involves a lot of fun, frolic and dancing,  you must be careful while choosing the music system. A lousy music  system would be a mistake that will not be pardoned by anyone. Some  lighting effects on the dance platform enhances the grace of the dance  performances. After all the planned dances and songs, it is good fun to  leave the floor open for everyone to do some free dancing and celebrate  the success of the event. This is when the DJ comes into picture. Also  those who could not prepare their dance performance for the show, now  get a chance to dance. A perfect DJ can be a great entertainment for  those dancing and for those watching. This would give a spectacular end  to the ceremony.