What is a good response for bar and bat mitzvah invitations?
There's nothing special. Simply say "Yes, I look forward to attending", or "I regret that I will be unable to attend, but thank you for the invitation". If you want to add something extra, you also say "Mazel Tov", which is a Hebrew expression for offering congratulations on special occasions. A gift is up to you, depending upon your relationship to the family that offered you the invitation. If you want to send a gift, a check or a gift card to the young man or young lady are appropriate.
About how much does a wedding invitation weigh?
Most wedding invitations weigh 1-2 ounces, however, that will vary depending on the weight of the paper, embellishments, etc.
What does "dress to impress" mean?
We should always dress to the best of our ability based upon the occasion. However, few of us take to much time dressing for a trip to Home Depot a trip adding the corner to 7–11. Dress to impress is a phase often used when talking about going for an interview for a job, meeting future inlaws, when joining a club or going out to dinner with the boss when corporate higher ups are in town. It means wear better than your best. For women there are significant differences in which clothes are are appropriate for different occasions. Dressing to impress often also includes a near mandatory trip to the manicurist, the hair stylist, a higher end department store and now days even a make up artist.