The skillset of design is a weakness from our team, we found fantastic and free handwritten fonts to use, but how can we draw the little arrow to the feature? How does that dark screen come up in onboarding design ( with the app underneath) is there an app for this that I can design the screen shots for our developer for our onboarding storyboards? Help? Bootstrapping!
You need to provide more information about what tools you are currently using.
For the purpose of creating wireframes, I would suggest using Balsamiq, and avoid doing any styling at all. This is good for the phase when you are working out screen flow and layout.
If you are doing a mockup, i.e. something that can look like a screenshot and will determine the graphic style of the app, then you really need to work with a graphic designer. Would you ask a non-programmer to write code? It's the same with graphics -- there's no substitute for a professional. At the stage you're at, you should be able to find an independent freelancing designer quite inexpensively in any decently sized city.