This glitch is rather easy to use and it benefits both your relationship with Karen and your dog's affection level.
To perform this glitch, simply take your dog to Karen and talk to her many times when you are holding it. It is best to do this when she is inside a building because it takes a while. As you are talking to Karen, you will see her heart level rise.
There are two side effects to this glitch. First, Karen will be at a red heart (or where ever you stop). To marry her, all you need is the kitchen and a blue feather. Also, your dog will like you more. If you feed him and pick him up and run him every day, he might be able to win the first Winter Dog Race.
Just let your cow get sick by not feeding it or leaving it out in the rain and give it the animal medicine. You will probably have to do this three or four times to get large milk. After two times you should have medium milk. And after three times you should have large milk.
NOTE: This trick will not work to get Gold Milk!
Go to the Flower Shop, not in, just in front of it. Look at the first link of fence on the LEFT side, from the front. You should be able to walk through that one link of fence. NOTE: doesn't work on right side.
On festival days, it will always be sunny no matter what the weather report says it will be.
To get infinite music boxes, first go find the treasure map inside the tree in the northeast corner of your farm, then wait until summer and follow the instructions on the map. After yuo dig it up, take it to Rick who will fix it, and then give it to a girl to make her like yoou a significant amount more, and then you can do it again and again and again all summer.
While your baby is in the crawling phase bring him to the bathroom in your house and set him outside the door to the bath tub. If you pick your baby up quickly and then immediately open the door you will go into the bath tub and come out holding an invisible baby, if you press Z it will say your baby'e name, but you won't be able to see it. It takes a couple tries to get the timing right, but it works.
If you want to get rid of your dog, than just bring it in the bathroom and place it on the ground. Then let it walk around and eventually it will walk into the black where you can't walk and it will fall down some sort of hole. You can call for it but it won't come, you will just hear it's barking. WARNING: There is no way to get your dog back, so don't save unless you don't want a dog.
To get an invisible horse, ride on it until 5:59AM. When it becomes 6, the day restarts and you are back in your house, only you are riding an invisible horse! You can jump off and call it again and ride it, but only inside the house.
THIS GLITCH IS HARMFUL. You CANNNOT get it back outside, so don't save unless you don't care about your horse.
If you go in the mountain hot spring at 5:59pm or right before you're sent back home at six. Your character will wake up the next morning and will glitch to an invisible you, you wrapped in a towel, and normal you.
-=WARNING=-=WARNING=-=WARNING=-=WARNING=-=WARNING=-=WARNING=-=WARNING=-
After you have turned invisible it is IRREVERSABLE, you can NOT change back! So be sure NOT to save afterwards unless you want to stay invisible!
This glitch can be performed on any of the girls. In order to perform this glitch, you must not be married. You can then choose among any of the 5 girls in the game that you wish to have two kids with. The girl that you choose must then marry the rival. Afterwards, start giving the girl gifts until she reaches a pink heart. Next, buy a blue feather, and make sure you already have a kitchen built (since it's a marriage requirement). You must then propose to the rival's wife before they become pregnant with the rival's child. She will say something along the lines of not accepting it, but the blue feather will disappear and you and her will in fact be married the next Sunday. Once you meet the requirements of having your child and your rival's child, they will be born. Your rival's child will be born first and your child will be born second if the glitch is performed correctly.