Is this the correct way to write script using Selenium web driver? and how I can improve this code?

Below is the code to automate Amazon.com from search to payment page and it works perfectly fine. I am new to selenium. SO what factors I should keep in mind while writing a script? and What more improvement I can make to this code? please advice. Is this the correct way to write script using Selenium web driver? how I can improve this code ?

WebDriver driver;

    @BeforeTest
    public void connection()
    {
          System.setProperty("webdriver.chrome.driver", "\\chromedriver_win32\\chromedriver.exe");
          driver = new ChromeDriver();
          driver.get("https://www.amazon.com/");
          driver.manage().timeouts().pageLoadTimeout(20,TimeUnit.SECONDS);
          driver.manage().window().maximize();

    }


    @Test (priority =1)
    public void select_department() throws InterruptedException 
    {
        driver.findElement(By.xpath("//div[@class='nav-search-scope nav-sprite']")).click();

        WebDriverWait wait = new WebDriverWait(driver,10);
        wait.until(ExpectedConditions.presenceOfElementLocated(By.xpath("//select[@id='searchDropdownBox']")));
        Select department = new Select(driver.findElement(By.xpath("//select[@id='searchDropdownBox']")));
        department.selectByVisibleText("Appliances");   

        driver.findElement(By.xpath("//input[@id='twotabsearchtextbox']")).sendKeys("microwave");
        driver.manage().timeouts().implicitlyWait(5,TimeUnit.SECONDS);
        driver.findElement(By.xpath("//div[@class='nav-search-submit nav-sprite']//input[@class='nav-input']")).click();
        driver.manage().timeouts().implicitlyWait(20, TimeUnit.SECONDS);
    }


   @Test (priority =2)
   public void filters() throws InterruptedException
   {

       // Click on Brand filter
        String brand = "Panasonic";
        WebElement ul= driver.findElement(By.xpath("//div[@id='brandsRefinements']//ul[@class='a-unordered-list a-nostyle a-vertical a-spacing-medium']"));
        List<WebElement> li = ul.findElements(By.xpath("//span[@class='a-size-base a-color-base']"));

        for(int i=0;i<li.size();i++)
        {
            String span = li.get(i).getText();

            if(span.equals(brand))
            {
                li.get(i).click();
                break;
            }
        }

        // Price Filter
        driver.findElement(By.xpath("//input[@id='low-price']")).sendKeys("50");
        driver.findElement(By.xpath("//input[@id='high-price']")).sendKeys("100");
        driver.findElement(By.xpath("//span[@id='a-autoid-1']//input[@class='a-button-input']")).click();



   }    

        @Test(priority= 3)
        public void listepage() throws InterruptedException
        {

        String URL = driver.getCurrentUrl();

        //Scroll down the page
        JavascriptExecutor jse = (JavascriptExecutor)driver;
        jse.executeScript("window.scrollBy(0,1000)", "");

        // Select a random Item from list page
        driver.findElement(By.xpath("//span[contains(text(),'Panasonic Microwave Oven NN-SD945S Stainless Steel')]")).click();
        driver.findElement(By.xpath("//input[@id='add-to-cart-button']")).click();  

        WebDriverWait wait = new WebDriverWait(driver,10);
        wait.until(ExpectedConditions.presenceOfElementLocated(By.xpath("//*[@id='attach-accessory-pane']/div/div[1]")));

        driver.findElement(By.xpath("//*[@id='attach-sidesheet-view-cart-button']/span/input")).click();
        driver.navigate().to(URL);

        driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

        jse.executeScript("window.scrollBy(0,1000)", "");

        driver.findElement(By.xpath("//span[contains(text(),'Panasonic NN-SB646S Countertop Microwave Oven')]")).click();
        driver.findElement(By.xpath("//input[@id='add-to-cart-button']")).click();  
       // driver.manage().timeouts().implicitlyWait(30,TimeUnit.SECONDS);
        Thread.sleep(10000);
        if(driver.findElement(By.xpath("//*[@id='a-popover-7']")).isEnabled())

        {
            driver.findElement(By.xpath("//*[@id='siNoCoverage-announce']")).click();
        }

        else
        {
            System.out.println("==Protection plan div is not enabled");
        }

        wait.until(ExpectedConditions.presenceOfElementLocated(By.xpath("//div[@id='huc-v2-order-row-container']")));

        driver.findElement(By.xpath("//a[@id='hlb-ptc-btn-native']")).click();

        }

        @Test(priority= 4)
        public void signin ()
        {
        driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
        driver.findElement(By.xpath("//input[@id='ap_email']")).sendKeys("");
        driver.manage().timeouts().implicitlyWait(3, TimeUnit.SECONDS);
        driver.findElement(By.xpath("//input[@id='continue']")).submit();
        driver.findElement(By.xpath("//*[@id='ap_password']")).sendKeys("");
        driver.findElement(By.xpath("//*[@id='signInSubmit']")).click();
        }

        @Test(priority= 5)
        public void delivery_payment_info() throws IOException
        {
        driver.manage().timeouts().implicitlyWait(20, TimeUnit.SECONDS);
        driver.findElement(By.xpath("//a[contains(text(),'Deliver to this address')]")).click();
        driver.findElement(By.xpath("//input[@id='order_0_ShippingSpeed_sss-us']")).click();
        driver.findElement(By.xpath("//div[contains(@class,'a-row a-spacing-medium')]//input[@class='a-button-text']")).click();
        driver.findElement(By.xpath("//*[@name='ppw-accountHolderName']")).sendKeys("test test");
        driver.findElement(By.xpath("//*[@name='addCreditCardNumber']")).sendKeys("2");
        driver.findElement(By.xpath("//input[contains(@name,'ppw-widgetEvent:AddCreditCardEvent')]")).click();
        String error_msg =driver.findElement(By.xpath("/html/body/div[5]/div/div[2]/div[3]/div/div[2]/div[2]/div[1]/div/div[1]/div/div[2]/div/form/div[1]/div/div/div")).getText();
        System.out.println(error_msg);

        File screenshot =((TakesScreenshot)driver).getScreenshotAs(OutputType.FILE);
        FileUtils.copyFile(screenshot, new File("C:\\test123.jpeg"));

   }