Steps I Recommend
Ensure your Blogger blog is using custom domain. if not, switch to custom domain.
Purchase web hosting plan for your WordPress blog. You can try this host. It rocks
Once your hosting plan has been activated, sign in to your cPanel and install WordPress.
Change your custom domain nameservers to that of your new host and chill till you can access your installed new WordPress site in your Web browser. Alternatively, you can get things done on a subdomain as explained here before making changes to your domain DNS.
Once you can access your new WordPress site in your web browser, sign in to your WordPress dashboard and delete the sample post and sample page.
Thereafter, go to Settings -> Permalinks and select Custom Structure option and paste the following value next to it and save changes.
Thereafter, install the “Blogger Importer Extended” plugin and use it to export your Blogger posts (including images and comments) to the WordPress site. Alternatively, you can export your Blogger blog and use Blogger Importer plugin to import the file to your WordPress site.
Once your posts are successfully imported, ensure the links are intact by running the script shared in this post. - Very Important!
You can install Post Date Change Redirection plugin to fix handle changes in post dates…
You can proceed to fix some redirections eg the m?=1 redirection, feed redirection etc
You should also watch out for 404 pages in the long run and redirect them accordingly.
I will share more tips in the long run and you can check them via the #blogspot2wordpress tag.