In all likelihood, your Bid Proposal will be competing against the Bid Proposals of other businesses. To create the best possible Proposal and give yourself the highest chance of securing the project, you should consider:
carefully reading and reviewing the initial invitation to bid - by making sure that your bid corresponds with the client’s requirements, you increase your chances of winning a tender
supplying relevant information about your business - identify whether your business specialises in the work you're bidding for or whether you're more of a generalist, and set out what makes you stand out in your industry. Your Bid Proposal should highlight why this makes your bid worthy of winning
giving reasonable time and cost estimations - while everyone wants work to be done quickly and efficiently, there's such a thing as ‘too fast’ and ‘too cheap’. You should avoid giving unrealistic estimates in your Bid Proposal. It shows the receiving party that, although you might not have the fastest or cheapest estimate, you're being reasonable. That can go a long way
providing project specifics - be specific about your knowledge and expertise in your Bid Proposal. Note all the details and explain how you came to your estimates of price and time