Make sure you get a clear idea BEFORE submitting your proposal of what the decision making process looks like:

Who makes the decision
What are the key criteria
When will decision be made
What happens after bids are received
If a new vendor is selected, when will they start?

Ask for a commitment from whoever you deliver the bid to to stay in touch with you and to notify you when a decision is made
Once you make this request (whether in person, via email, or over the phone) WAIT for a response, before assuming you have it. Don’t agree to submit you bid without it

Let your prospect know that this is a custom proposal and (as one professional to another) you expect the courtesy of a notification
When following up use phrases like “checking in” and “touching base” to find out when a decision can be anticipated (and where in the process things currently stand).

DON’T make a nuisance of yourself- understand that corporate wheels turn ever so slowly

Stay busy enough submitting other commercial proposals that you don’t have time to obsess about any one pending deal