You've taken the first step. That of recognising that your diet needs to change.
The next step is to make the actual change.
Find fruits that you like and stock up. Promise your self that you will replace a part of the unhealthy food you eat with 2 to three servings of fruit every day.
Start drinking plain water. Start with two 8 oz glasses a day and work it up to around 10.
Once you get used to eating fruit, then find some veggies you can eat raw like baby carrots, cucumbers, tomato, baby corn, green peppers, tender cabbage, bean sprouts, sugar snap peas, baby spinach. Buy small quantities and reduce some more meat and bread on your plate and replace it with veggies that you have sprinkled with some ready made low fat dressing.
Meanwhile continue to eat the 2 to 3 servings of fruit.
Once you are used to eating raw veggies try cooked ones like steamed or stirfried green beans, broccoli, bok choy, spinach, swiss chard, carrots, peas, zucchini..... the list is endless.
Once you are used to this, add other vegetarian foods like canned kidney beans, chick peas and other beans that you see at the market.
Switch to whole grain bread and whole wheat bagels. Replace carbonated beverages with non-sweetened fruit juices and low fat youghurt and skim milk.
Learn to cook so that you do not have to eat out at fast food joints. Find someone who can help you learn cooking and arrange to take lessons.
Take these steps one at a time so that you do not feel overwhelmed. We all have some veggies and fruits we dislike and some we like and some we love. Find your own likes and loves by experimenting.