Arrangement of contests in social networks will make you more popular and will increase your sales. The only precondition is that the contest should be interesting and unusual.
Giveaway contests become more and more popular, thus, most of them have pretty common and usual conditions. Often you should simply repost the contest on your page and follow the organizer's account. According to our statistics, about 90 % of Giveaway contests have similar conditions and are typical.