Here are some suggestions (these are NOT halachot!) of what to prepare in advance of Shabbat. Add or delete to suit your needs!
 
Candle Lighting

• Check candle lighting time
• Set the candles in their holders (and have matches nearby)

 
Set the Table
Set the table, including the challa and its cover and the wine cup.
 
Kitchen Preparation

• Sharpen knives
• Tear paper towels
• Refrigerator: Turn off or unscrew lights; disconnect any LEDs or fans
• Set up blech
• Set up hot water urn
• Turn off stove, oven

 
Food Preparation

• Thaw frozen meat, fish, and other food that might take hours to defrost before being cooked
• Cook whatever can be cooked ahead of time on Thursday night, Friday morning, or earlier in the week
• Squeeze lemons; do any other boreir-type preparations
• Chill wine
• Open bottles and cans that will be needed on Shabbat
• Prepare tea essence

 
Cleaning

• Make beds
• Sweep or vacuum
• Dump garbage

 
Clothing

• Do laundry
• Empty pockets of muktza (or if there is no eruv, of everything!)
• For men, set out Shabbat talit

 
Muktza
Check that nothing you will need is beneath a muktza item
 
Personal Care

• Cut hair and nails, if needed
• For men, shave or trim beard and mustache, if needed
• Tear dental floss
• Tear toilet paper or put out tissues in bathrooms
• Open any new boxes of tissues

 
Electronics

• Set heat or air conditioning
• Turn on or off lights, or set timers for them
• If desired, turn off or disconnect:

• Alarms 
• Cellphones and phones
• Computers
• Microwave detectors
• Other electronics

 
Eruv
Check that the eruv (if any) is good