The best advice I can give is to use every tool you can, FedBizOpps, GSA Contract, etc. to channel opportunities to you.
Then, have a well-thought-out system for your “go/no go” filtering so you know exactly what is a worthwhile pursuit. Even better, have your system so clear and simple that your assistant can be trained on it.
When you have opportunities that you want to go after, streamline all that you can to save time. The more time saved, the more time spent on responding to more opportunities. It is a numbers game, so responding to more opportunities is key, but also keeping a good score of your batting average and trying to constantly improve.
Debriefings can help with this. And last but not least, follow the instructions with precision. One small mistake and the bid that took you 5 hours to write can be thrown right in the trash.