Darken the placeholder text colour of the newsletter signup form in the website footer to make it more legible. Use the following tool to determine a suitable level of contrast: http://webaim.org/resources/contrastchecker
Increase the size of the input field and the submit button.
There is not enough contrast between the placeholder text and the background - which makes it difficult to read and not very noticeable.
Signing up for the newsletter is likely to be a primary goal for email marketing and new customer acquisition - and the form could be displayed more prominently and have a stronger call to action (e.g. Sign up instead of > button) to encourage signups.