loozhengyuan,
here are my 'super short version' of to do list for your specific requirements:
1. prep your grandma that she may need to whip up more than one time of the same dish if the results are undesirable. so prepare ingredients for more than one dish of the same kind.
2. for the most basic method of making certain dish looks good, get your self a brush and some cooking oil. this is often needed to make the food looks 'shiny' to bring out the appeal. but don't go about spreading on anything and everything.
3. in addition to hot shoe mount flash, you might need a few pieces of A2 white mounting board to reflect light and also to direct the light in a certain angle to create certain 'shades' and 'depth'. for me, i prefer monobloc lightng with softboxes. my preference is 3 lights with modifiers such as snood, striplights, grids... but again, you might not want to scare your grandma with your arsenal... hot shoe mount external flashes are fine .. just that too many shots will result in inconsistent power output.
4. get a tripod if you are planning to shoot all the dishes in a consistent elevation and angle. otherwise, handheld is fine for creative as well as different elevation to bring out the effect of different dishes for different purposes.
5. when styling, keep things simple, don't mess up the whole plate. Also, if things look boring, isolate certain key ingredients rather than mix them all up on the plate. You might want to add some garnishing to spice up the dish. choose your plates and cutlery set carefully. Shapes and colors play a very important part of the styling equation. Check out what your grandma is cooking in advance so that you can compliment the dishes with the right cutlery set. Don't forget napkins. They are of good use, such as folding them and putting the dish on top to add some colors to the whole setup.
6. ok.. down to the camera equipment, you might want to have lens for closeup (macro is good, 200m works but you might need to go damn fall back to get the shot) and also lens for wider shot to get the whole table setup. Wide would be anything from 35mm to 50mm. 50mm would suffice and you just have to step backwards to get the effect.
7. last pointer for you... keep your lighting consistent. don't mix color and don't shoot a few dishes with natural window light and a few shots of other dishes with strobes or flashes. making them consistent would look good when compiling them into a cookbook. color temperature calibration is important so don't forget your custom white balance.
8. Book printing involves a lot more.. color adjustment, layout, selection of printer... etc.. but that is way beyond me. I only shoot and focus on shooting. the rest are done by the experts.
Hope this helps. Dream Merchant has said it rightly. Food photography is a damn difficult subject. I am still learning every time i shoot a food dish.
Enjoy...
I'm doing this because my grandma wants to publish a book on it . And want the best for her .