"A lot" is two words.
The phrases are "should've" (not 'should of'), "could've" (not 'could of'), "would've" (not 'would of'), etc. These are contractions. You are using a modal verb with the secondary verb, to have, and contracting them to represent how we slur the words together.
more than, less than, bigger than, older than, quieter than, faster than, etc
-- these are all comparison phrases. Notice that than is spelled with an 'a', not an 'e'. The word, then, is used in reference to time: 'this first, then that'.
'Your' is possesive... it does not mean 'you are', that would be the contraction, 'you're'.
When you use 'your', it is refering to something that you possess. 'Your car', 'your clothes', etc.
'Their' is possessive, it doesn't not mean 'they are', that would be the contraction, 'they're'.
'Their car', 'their clothes', etc.
'They're going on a vacation to Germany.'
'There' is a location. 'What is over there?', 'If it's not here, then it must be there.'
Okay, enough ranting.