I get to work yesterday and then realize that I gave you two tips yesterday and carried on about why you should do it that I never suggested ways to fix the problems. Talk about your DUH moment.
Ok lets start with fertilizer. You can't go wrong with compost spread upon your lawn. You can easily make your own or buy it. If you know someone with cows that works too. (and it's not as smelly as you would think) Don't use horse manure without composting it first. Unlike cows with their four chamber stomachs, horse manure will have weed seeds in it that you don't want in your lawn or garden.
Next Pest control. Lets face it good old Mother Nature has already supplied us with the solution to our pest control problem. You just need to invite them to your yard. Think Bat houses or Purple Martin houses to help control those mosquitoes. Add natural hiding places for toads, frogs, and lizards. Then a tree or dense bush for birds. Song birds are great for getting rid of snails and slugs. For every problem insect there is something that eats them. Hit your local library to find the natural pest control for your problem bugs.