Posted: 22/03/2015 at 20:14
still time to renovate that lawn.
I would apply a lawn weedkiller/mosskiller then a week or so later rake quite vigorously. it will look awful then but don't panic. if it's reasonably level apply a dwarf rye grass mixture...a very hard wearing popular seed mix. If there are some high spots or hollows try to level them out and then sow seed.
keep surface moist....not wet...until germination and try to keep off until growing well.
best not to apply a granular feed now because you've sown seed but 6 weeks or so later use a liquid nitrogen feed. Another 4 weeks later you can liquid feed again to achieve a nice green lawn.
regular mowing.......once a week if you can.....and some treatment in the autumn will help keep your lawn healthy.