It is appropriate to provide guidance or suggestions to the person writing your letter of recommendation for an award. You can help ensure that the letter accurately reflects your accomplishments and demonstrates your most vital and relevant qualities by giving advice or tips. You can also provide the writer with specific examples of your achievements or work they may not know. However, it is essential to remember that the letter should ultimately be the writer's own thoughts and opinions, so be sure to communicate your guidance or suggestions respectfully and with the understanding that the writer may choose to incorporate or omit specific details based on their own perspective.