Thin lawn

dark9

hi first post im looking for advice or things to try with my lawn so far ive got rid of the moss and aireated feed in autum and summer with a four in one the lawn did thicken up for a few weeks but now it's looking thin and patchy again was wondering it I should try top dress and seeding the lawn in the back is thick and looking well also got a few clumps of a scruffy looking grass not sure but looks like Yorkshire fog  

I've taken a few photos after a cut any help idea will be appreciated 

dark9

Bump 

Fairygirl

Some moisture will help to green it up. If the weather's been dry that's the usual reason. You can help avoid that during the warmest weather by not cutting so short. Never take more than about a third of the height off at any time. Little and often helps the grass thicken up.