How can I make onpage SEO in my wordpress site? After google submission and sitemap.xlm submission how can I check it that it works properly. Is there any way sothat I can check it manually? Please help me.
I think your site map when create and when you xlm site map code put your site then a confirmation notification or Xlm activation states was showing in your mail. or You will logging your xml site map site and go site map states if show a green signal its works properly.
If you have Google Webmaster Tools, sign in to your account, and look in your site profile under “Optimisation”. You’ll find an add/test sitemap button there. If you don’t have a GWT account - sign up for one now. 
Well, submitting your sitemaap is not the top of your SEO efforts. The least you can do is write the proper title, keywords description. Install a SEO plugin (there are many available), and it’ll show you the fields for meta tags, SEO by yoast can check the settings for better results.