To check broken links, broken images, spell check, grammar etc Use “web link validator”.
To check Validation & Accessibility testing for (HTML, CSS, Javascript, Meta tag, Headings, sitemap, url, Doctype, image size, page size, broken links, responsive etc) use sitecheckup and provide detailed report.
To check browsers compatibility as well as cosmetic issues run site/application manually on each browser as well as use different tools like ie tester.
To check validations/strength of input fields/forms use different strings
Move forward and check manually functionality/business flow
Then check security like xss (cross site script), sql injections, blind injections, brute force attack etc use manual scripts as well as use automation tool “Acunetix”, provide report if requirement.
To check load/stress/performance of site/application check manually to load heavy images as well as use “google analyzer”, Compuware, loadrunner etc, provide report if require.
Develop bug report with each and every screenshots and provide video of a bug, if necessary
Report tool Excel, google docs etc (provide url of Bug report and screenshot)
And last but not least Mobile testing of all devices included IOS, Android & Blackberry.