Guess ties were designed by friend (8)
I believe the answer is:
estimate
'guess' is the definition.
('estimate' can be a synonym of 'guess')
'ties were designed by friend' is the wordplay.
I cannot really see how this works, but
an anagram of 'ties' is 'esti' which is present in the answer.
'by' could be 'at' and 'at' is present in the answer.
The remaining letters 'me' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for estimate that I've seen before include "Quotation" , "Make an educated guess" , "rough judgment" , "Make approximate judgement of size or amount" , "Evaluate - approximation" .)