What are some tips you have when writing topic sentences and could you provide some formats when writing them?

A topic sentence is important to set the tone for your readers while providing the theme and organizational format of your piece.
There are 3 things I learned when developing topic sentences. The first important thing is to introduce your topic while keeping it simple. A common mistake is being too wordy and this ends up confusing your reader.
Second, when writing a sentence that introduces your stance on the topic lists the reasons for your stance (your outline for the rest of the piece) without expanding into detail. Save expanding and details for each part of the body paragraphs.
Lastly, try to make the sentence catchy and captivate your readers. You ultimately want your readers to WANT to read more. Show your enthusiasm about the topic within the first sentence to have your passion come through to your readers.
Here are some examples of topic sentences that organize your piece, entice the reader, and introduce the topic.
If your writing is about you're love for something, such as the Adirondack Mountains you could write "The Adirondack Mountain range is a beautiful and majestic landform that lures people from all over the world to climb and enjoy their beauty, overcome their great challenges, and succumb to their over all humbling power."

If you are writing to compare stances on an issue, your topic sentence may look like this: "Decriminalizing Marijuana has the potential to boost our nation's economy while helping many people who are suffering from devastating illnesses or increase recreational drug use and number the of crimes and incarcerations related to drug use."
I hope you find these tips and examples helpful!

Your topic sentence serves many purposes. It can set the tone for your piece, introduce both the subject and your opinions on the subject, as well as provide an outline for the writing to come. In a way, your topic sentence works as a map for the reader to follow as they travel into your piece.
I have been an avid writer for as long as I can remember, and I learned early-on the importance of a strong topic sentence, so here are a few things I learned along the way that will hopefully help you to be able to construct a clear and concise topic sentence.
First of all, keep it simple. Make sure to cover only what you plan on discussing in the paragraph to come. Avoid going off onto tangents that may be related to the topic in some way, but are not necessarily what you wish to expound upon in this particular piece. Use commas to set off any items in a list that you will later explain more thoroughly.
Giving examples of topic sentences is a little bit more difficult, but I can give you a couple. If you are writing about why you love Canada, for example, your topic sentence could be, "I love Canada for its amazing cuisine, breathtaking scenery, and diverse culture." If you are writing about a two-sided political issue, your topic sentence could be, "Many people believe we should do away with social-welfare programs, but there are a multitude of reasons why this would ultimately be detrimental to society."
Each of the example sentences lays out a map for both you and the reader. The sentences make it quite simple for you, the writer, to consciously write out supporting information, and the sentences prepare the reader for what is to come so that they can analyze and interpret your writing