Re: electrical estimating
Take your labor rate, multiply it by the amount of hours you expect the work to take. (Give yourself some allowances) Add this number to the cost of labor and whatever markup you deem resonable for the material. (I mark up material from 40% to 60%) Once you receive this total, add whatever profit you expect for the job. (I tend to use 15% to 25% depending on size and level of work)
Keep a log book of every job you do and the total labor and material cost that were assoicated with that job. This will allow you to readily access the information to make future acurate estimates.
Outside of the numbers game, add incentives to your bids to make them more attractive. Things like 1 year guarantees, free return inspection of installed materials and equipment, senior discounts, military discounts, and so on.
The most important aspect of successful bidding is personal involvement. Hand deliver proposals. Explain them out in relative detail. Provide a smile and a handshake. I have won more jobs from simply being courteous and spending a little time going over the plan with the customer than from being the lowest bidder. It almost assures return work for the life the client. Good luck and hang in there. PRACTICE!