At B1 level you can understand the main points of clear standard input on familiar matters regularly encountered in work, school, leisure, etc. You can deal with most situations likely to arise whilst travelling in an area where the language is spoken. You can produce simple connected text on topics which are familiar or of personal interest. You can describe experiences and events, dreams, hopes and ambitions and briefly give reasons and explanations for opinions and plans.
You can start up a conversation and help keep it going by asking people relatively spontaneous questions about a special experience or event, expressing reactions and opinions on familiar subjects. You can have relatively long conversations on subjects of common interest, provided the interlocutor makes an effort to support understanding. You can follow clearly articulated language directed at you in everyday conversation, though will sometimes have to ask for repetition of particular words/signs.
You can express and respond to feelings such as surprise, happiness, sadness, interest and indifference. You can express your thoughts about abstract or cultural topics such as music or films. You can explain why something is a problem. You can give brief comments on the views of others, can compare and contrast alternatives, discussing what to do, where to go, who or which to choose, etc. You can express beliefs, opinions and agreement and disagreement politely. You can invite others to give their views on how to proceed.