Gabby,
Your evidence should show that you are:
both over 21 (unless your UK spouse is a member of the UK Armed forces - passport and birth certs);
are in a genuine and subsisting relationship (photos, phone bills, emails, letters of support from family and friends, mutual correspondence);
Maintenance and accommodation (tenancy/mortgage agreement, independent surveyors report is useful, bank statements and payslips, savings, offers of employment). Maintenance and accommodation are crucial aspects.
Enclose a letter listing the requirements and how you meet each one. A income and expenditure sheet will also help. The average waiting time is about 12 weeks, although some of my clients have obtained their visa in one week.
If you are really anxious I produce a range of
eBooks on this subject; you might find the one on Marriage applications useful.
But don't rush things. Go over everything carefully; you've got the rest of your lives to look forward to. Good luck.