One of the basic milestones that many people forget is this:
Get Customer Number One.
Sometimes people forget these even before getting funded (wow!).
- michael vizdos
This depends on your business, of course, but typically you will want to show that you are running as a viable business on the operations side (that you have clear processes and team members have defined roles and responsibilities). You will want to have established your market (i.e. have some customers) and demonstrate an ability to both retain and attract new customers (i.e. grow). If you do not yet have a product that is launched or ready to launch, you should probably show that you are working on an iteration or maybe even a pivot, if you're really not getting anywhere. How a startup deals with failure in the first year often says more than how it deals with success.
Best benchmark: Get a paying customer who isn't in your inner circle of friends or family. If you can hit that benchmark, it means you've literally knocked out laundry list of other obstacles that many startup blogs will outline.
If you can't achieve that, then analyze why and there's where you put your effort. If you need money to hit that mark, then you better be a good pitch person or have previous track record - otherwise, you're fighting an uphill battle.