The dirty dozen

Words or phrases whose meaning I confuse in Spanish. In most cases it's because they are "falsos amigos" - they sound as if they should mean something else. For clarity, I will post only the correct meanings here. It should be clear in most cases where the confusion lies.

• por cierto : by the way
• por supuesto : of course
• a lo mejor : probably, maybe
• por desgracia : unfortunately
• sin embargo : however, still
• a menudo : often
• tal vez : maybe
• ahora mismo : right away
• tal y como : just as
• por lo tanto : therefore
• en seguida : right away
• por lo menos : at least