You don't have to be very experienced to realize that everyone has difficulty accurately assessing how s/he or their magic performance is being perceived by others. Requesting feedback from those you trust can be one of the surest ways of improving your performance.
"Unsolicited advice may easily be perceived as criticism" remains as true as ever. If you have a piece of feedback for another performer, ask if they want to hear it. If not, respect that.
In addition, you might consider asking them on which parts of the trick/routine they wish feedback (i.e. the moves, scripting, the flow of the routine, etc.) and the question "is this a good time for me to give you the feedback" is always an appropriate question. Some days are better than others.
Commend + Recommend + Commend is not a bad equation for creating balanced feedback. Strive to find two items in the performance worthy of praise to include with one that you believe could be improved. Additional note: Then seek not to link those three together with any conjunction.
Giving your respectful feedback in writing allows the other person to prepare themselves for reading it when they're in the best frame of mind to benefit from it and referring to it again over time - processing it, applying it or asking questions about it to get the most from it.
Using the OMS Feedback Form might help you get started.
As used by the international magic competition FISM here are the definitions of the various categories the Omaha Magical Society uses in providing feedback when requested on the performances of others in the club.
♠ Does the performer evoke a feeling of wonder, surprise and mystery in such a way that the audience cannot detect the secret or dexterous handling that causes it and therefore can only attribute it to magic? Please differentiate whether or not you're viewing it as a fellow magician or as a member of the general public.
♠ Is it an act that is primarily ‘magic’ in nature? Are magical events taking place throughout the act, or are they mainly supporting another form of entertainment?
♠ Presence: projection of personality, command, confidence, appropriate energy etc.
♠ Appearance: wardrobe, costumes, stage setting, display of props etc.
♠. Stagecraft: movement, use of music and light, visibility of action, voice projection, handling of assistants, volunteers, live-stock, props etc.
♠ Overall Impression: - is the magic direct, logical and understandable?
- is the character the magician plays in line with the magic s/he performs and does s/he stay in character throughout the act?
♠ How enjoyable is the act?
♠ How is the audience reacting?
♠ How is the act structured?
♠ Does it flow smoothly from start to finish?
♠ Is the opening impression strong?
♠ Does the act build up to a recognizable finish?
♠ Is the program content (theme, choice of material) appropriate?
♠ As an Art form, does the act, in one way or another, appeal to the EMOTIONS of the audience?
♠ Does the performer show technical mastery of the props and sleights he uses?
♠ Is he performing material within his technical skill?
♠ Are there technical difficulties and, if so, how does he handle them? How skilled is he in the use of misdirection?
♠ Are there ‘flashes’ or ‘exposures’?
♠ Is the audience fooled by some or most of the effects?
♠ Is there anything new and creative in the effects, the method or the presentation?
♠ Are there any novel ideas?
♠ Does the magician portray an original type of character?
♠ Does s/he use unusual articles with a rationale?
♠ Are seemingly unrelated effects connected in a way that makes for creative effects?