Shukla Ekadashi is the name for the 11th Tithi (lunar day). It's the 11th Tithi of Shuklapaksha. It's nature is Anand Prada, which can be interpreted as "inculcates happiness", "leads to Ananda". It's good for following works: marriage; religious works, Alankar, Upanayana, Devotsava; Vrata, fasting, completion of fasts; jewellery; painting, learning of sculpturing, clothes designing, dress, dance; travel; enter, starting of house, manufacturing of drinks, trade. This day has special religious significance in Hindu tradition, usually it's observed by fasting and almost every Ekadashi has it's own meaning and purpose.
According to classical Brihat Samhita Rudra rules Shukla Ekadashi, thus fasting, devotional activities, and remembrance of Brahman are very favorable. According to Muhurta Chintamani, Vishvadeva ("deity of particular class that answer to the concern that no divinity should be omitted from praise" (c) Renou, Louis. L'Inde Classique, vol. 1) rule this day.
Being Nanda (that can be translated as "prosperity", "good", "happiness") and ruled by Shukra (Venus), 11th Tithi of Krishnapaksha is suitable for following works or actions: related to clothes; dance, vocal music, festivals, art & sculpture, painting; farming, house, clothes, Aalankar (ornament, decoration); enjoyments, Tantris Kāryas.
During the vedic month Pausha Shukla Ekadashi becomes Sompad (that can be translated as wealth, possession, success) Tithi, which is considered very auspicious in succeeding in works started during this Tithi. Also in Pausha Shukla Ekadashi is Dharma Savarni - Manvadi Tithi, which is considered to be extremely auspicious for any Punya Karma (Japa, Tapa, Dana, Havan, Homa etc.). But being Manvadi Tithi Shukla Ekadashi should be avoided in starting of education, Upanayana, marriage, ending of fasts, construction of house and entering thereof; travelling; plantation works.
During the vedic month Ashwin Shukla Ekadashi becomes Maasa Shoonya Tithi, which is considered inauspicious in succeeding in works started during this Tithi.
Lagna (ascendant or rising sign) during Shukla Ekadashi becomes Tithi Shoonya (Lagna which is ruined by Tithi) for times when it is Dhanu (Sagittarius) or Meena (Pisces). Rohini Nakshatra also becomes Tithi Shoonya if it falls on Shukla Ekadashi. It's considered that all auspicious works done during Tithi Shoonya periods will be destroyed.