Hey Allison,
You'll need to provide the code + screenshots for us to be able to assist.
Also obligatory: strongly recommend investing in a tool like Litmus or Email on Acid for your email testing; coding for email is difficult because we need to account for a high number of environments with a lot of variability and frequent updates in OS. Using a testing tool is really the only effective way to be sure that your emails look good for all your recipients - plus some tools have the ability to add tracking code that will help you identify what email clients your database is using and therefore which ones you should optimise for.
Marketo templates are great starting points, but most of us move to custom templates fairly quickly to account for optimisation and brand requirements; there's quite a few third parties that are known around community to deliver high quality, responsive templates at fairly low cost. If you're finding Marketo's starter templates aren't working for your needs + don't have internal resource to support with coding, this may be an option to look into. I haven't personally worked with any, though I know that people have had good experiences with Email Monks & Knack.io. A quick search on community will probably show others too.
Hope that helps.