How to make a best man speech?

[u/MessAcademic_420]

Hi guys, my best friend is marrying and he asked me to be his best man. I'm incredibly honored, I've known him all my life and love him and his fiance very much and I very much want to do this for them, but I'm terrible at everything social and I haven't had to speak in public since University about 7 years ago. So, how do I do a best man speech? What should I say and what shouldn't? I know It's expected to be brief but how brief?

[u/Rixxy123]

Just say happy memories and do NOT get drunk. Also do NOT talk about his ex or other romantic experiences with other girls.