Q:

Keep track of your rejected edits

It seems you don't get informed in the upper Inbox message in case one of your edits got rejected.  If an edit got accepted you see the +2 Rep in the recent Reputations, but you never know if something was wrong with one of your edits if you don't keep track of them yourself. 
Since you don't get an information message in this case (see Decision on rejected edits should be displayed as a notification to the editor) How is it possible to track them yourself? 

A:

You can get your rejected edits from the Stack API
The topic User has an entry for Me Suggested Edits
Make sure you hit the button Get Token first before you hit Run. 
and don't use IE because it won't give you a token...

The result will look like this:
"items": [
    {
      "proposing_user": {
        "reputation": 13205,
        "user_id": 578411,
        "user_type": "registered",
        "profile_image": "http://i.stack.imgur.com/qj33e.png?s=128&g=1",
        "display_name": "rene",
        "link": "http://stackoverflow.com/users/578411/rene"
      },
      "approval_date": 1298996673,
      "creation_date": 1298996632,
      "post_type": "question",
      "post_id": 5157197,
      "suggested_edit_id": 11561,
      "comment": "layoutr of code "
    },
    {
      "proposing_user": {
        "reputation": 13205,
        "user_id": 578411,
        "user_type": "registered",
        "profile_image": "http://i.stack.imgur.com/qj33e.png?s=128&g=1",
        "display_name": "rene",
        "link": "http://stackoverflow.com/users/578411/rene"
      },
      "approval_date": 1298985879,
      "creation_date": 1298985799,
      "post_type": "question",
      "post_id": 5155003,
      "suggested_edit_id": 11482,
      "comment": "layoiut of the unions"
    },
    {
      "proposing_user": {
        "reputation": 13205,
        "user_id": 578411,
        "user_type": "registered",
        "profile_image": "http://i.stack.imgur.com/qj33e.png?s=128&g=1",
        "display_name": "rene",
        "link": "http://stackoverflow.com/users/578411/rene"
      },
      "rejection_date": 1298981760,
      "creation_date": 1298980107,
      "post_type": "question",
      "post_id": 5154076,
      "suggested_edit_id": 11442,
      "comment": "formatting  of folders"
    },

If you flatten the json you can get the links to your rejected edits like so:
var p = JSON.parse('{"items": [  { "proposing_user": {"reputation": 13205,"user_id": 578411,...... ');   // add all JSON here as one line...

var br, a, i, item, d = document.getElementById('r');
for(i in p.items)
{
    item = p.items[i];
    if (item.rejection_date)
    {
        br = document.createElement('br');
        a = document.createElement('a');
        a.innerHTML = item.suggested_edit_id.toString();
        a.setAttribute('href', 'http://stackoverflow.com/suggested-edits/'+item.suggested_edit_id.toString());
        d.appendChild(a);
        d.appendChild(br); 
    }
}

Here is a JsFiddle with my rejected edits...

A:

You can use the Data Explorer.  I created this simple query that will show you your rejected suggested edits.  The question title with just an ID displayed have been deleted. 
Using the API will give you access to real time data.  Currently the data explorer refreshes it's data once a week.