if you need some fancy presents to give away for 21 birth days or collage graduations an engraved flask is both memorable and affordable.
To engrave the flask I trace the image off my computer montier using boxing tape. Then I use my rotary tool to trace the outline of the image after I align the tape onto the flask.
the title image is a for a per-pharmacy student.

Step 1: Tools and Parts

roll of wide box tape
rotary tool: cheep harbor freights or dremel both work
computer screen: mine is a touch screen computer i would expect all screens to work
fine marker
flask

Step 2: Getting an Image

Look around the internet for inspiration on what to draw on the flask. A name in a cool font looks good if you cant think of anything.
If you have photo editing software go ahead and use it otherwise head over to Pixlr.com and use there free online photo editing.

Make a new photo with a size of 1024x768 pixels. Zoom in to 75% or so that the flask fits in it. Place the flask on the computer screen and trace around it filling everything that the flask dosn't cover.

Draw the picture you want to engrave in the white area, only draw it with one color because engraving can't add different colors.
thinner lines are better. a shape with the outline done looks good. Coloring in a solid shape ends up looking funny under different lighting.

Step 3: Transfering the Picture From the Computer

To transfer the picture get the widest tape that can be found. I used boxing tape.
Fold over an edge of the tape so that it is easy to pull off.
lay the tape on the computer screen so that the picture can be traced onto the tape.
I can fit most pictures in two strips of tape
the line in the center is to help you see the edge of the tape.

Use a fine point marker to trace the image to the tape
This image was done by first drawing lines with a ruler then placing the dots and symbols.
Be sure to look straight down on the picture where it is being traced because perspective will move the image.
It can be useful to do the picture in blue and trace with a black marker so it is easy to see.

If ink gets on the computer screen lighter fluid will take it off.

After the picture is traced the tape needs to be pulled off the computer screen.
Grab the edge of the tape that was folded over and pull on it slowly to get it off the screen.

align the tape on the flask then prepare to engrave.

Step 4: Engraving

For engraving use a small grinding bit and trace the outline.
Take your time and make sure the bit goes all the way through the tape.

when the engraving is done the tape needs to be removed, it is easiest to scrape it off with your finger nail then scrub off the residue with a rag and lighter fluid.