In general, transfers work best when the last bid was clubs. For example, transfers work well after (1♦)-2♣ and after 1♦-(2♣). When the last bid was made by an opponent, this also allows you to retain the valuable negative double and use the diamond bid as a transfer. For example, if you otherwise play transfer advances, you can easily play transfers on in auctions like (1♣)-1♠-(2♣) (double = negative, diamonds/hearts = transfer), but transfers don't work well in (1♦)-1♥-(2♦). I've also heard that some people play transfers effectively after 1♠-(3♣).