In my industry (service industry; carpet & air duct cleaning) we learn to avoid trying to close a sale while the client's arms are crossed. On the positive side of body language however, my ideal client was engaged (eye contact), open to my suggestions while I was speaking (arms un-crossed, either smiling or neutral but never frowning), and thoughtful (breaking eye contact only when considering my proposal, hand on chin and nodding). While these indicators may not always be overt or even occur while I am speaking with someone (which means I may need to put in more effort), they do help me know when to stop talking and just ask for the sale. Body language is a huge part of human communication which is why I always find it easier to make connections with clients and gate-openers when in-person.