Hi,
I have been in this for over a month. I have sent away 14 books away, and have many books in wish list as well. Every time I put a new book on the wish list, like CS Lewis and other well known books, there is none available in the system. Is that true always? I know the turn around time is often long, but what is the best way to perceive this situation of sending a lot, and not receiving any. Nor having the wish list books not in the system. Thank you for any help in how I am perceiving the reality of PBS. 
JP

Jeri, the definition of wish list is there are zero copies available and you are on a waiting list. For available books in the system you can click on "Order This Book".  

Here's an available book 

 Digital Sci-Fi Art : A Step-by-Step Guide to Creating Stunning, Futuristic Images

Do you only want hardcovers?  The more WL lines you are in the more chances you have of receiving them. You only have 15 on your wish list and only 1 edition of each book.  If you put every edition on your wish list and fill your wish list up, you will start receiving wish list books.

Also don't mail out anymore books until you spend some credits.  I only keep about 5 credits on hand and only post books when I need credits.  That way I don't have money tied up in postage.  You can put your bookshelf on hold and autorequest your wish list. Or just hold off on posting books until your credit stash gets low. 

Also it says you joined over a year ago. 

When we post a book, if there are other copies of the book already posted here, we get in line to have our copy requested.  If there are no copies posted, and there's a wish list line for the book, then our copy is offered to the member who is currently #1 in the wish list line.

When we want a book, if there are copies posted, we click the blue and white "order this book" button, and our order goes out immediately to the member who has been waiting longest to have his book requested.  If there are no copies posted, then we get in line for the book by adding it to our wish list.   If I'm #17 in the wish list line, then after the 16 members ahead of me have been offered a copy of that ISBN, the next time a member posts a copy, it will be offered to me.   (If you look at your wish list, you can see where you are in the WL line.)

It's likely that the 14 books you mailed out were all wish listed books.  The members may have been in line a long time, and were doubtless grateful to be offered your copy.  The 10 books on your bookshelf probably had other copies already posted here, so you are in line to have them requested.

It's hard to predict how long you'll have to wait to be offered the books on your wish list.  Some of the drawing books have a fairly short line, but then the number of members likely to post a drawing book is much smaller than, say, the number of member likely to post a best-selling fantasy book.  The wish list line for a best-seller may be longer, but the line may move a lot faster.

When it comes to best-seller books, they often have a long wish list line by the time they are published.  As some members buy the books, read them and post them, the wishes begin to be fulfilled and wishers find themselves moving up in the wish list line.  At the same time, other members hear about them, and add them to their wish list, so the line can stay long for a while.  Eventually enough copies will be posted into the system that there are no more wishes to be fulfilled, and the blue and white "order this book" button will appear on the listing.

Here are a few suggestions:

• add a bunch of books to your wish list now.  You'll start moving up in the WL lines, and eventually it will start paying off. 
• consider adding several editions of a title to your wish list.  For example, there are several other editions of "How to Train Your Dragon" you could add to your WL.  Hard to tell which wish list line will move fastest.  Unless you only want one particular edition, add as many as you like.
• don't post any more books until you start finding books to order
• go to literature map and plug in the name of a favorite author.  When I plug in Cressida Cowell, one of the suggestions of a similar author is Charlie Higson.  There are Higson books posted here that you could order now.  They have the blue and white "order this book" button, instead of the "+ wish list" button.
• find one of your favorite books here -- one you've already read.    Scroll down on the listing to see if there are any reviews by other members.  If there are, find a review you really agree with.  Following the date the review was written, there will be a gray link that says something like "12 more reviews."  Click on that to see if that member has reviewed another book you might be interested in.  Or click on the member's name to check out her bookshelf.  You may find a book you'll like that's currently available -- no wish list wait.

Some members start out here wondering how they can get more requests.  That can take a while, too, especially if they are posting books that already have lots of copies in the system.  You're having the opposite dilemma, but I suggest that you look for some books by authors you haven't tried yet that have copies posted while you wait to move up in the wish list lines for the books on your WL.  Your advantage will be that when you find books, or when your WL books are offered to you, you won't be scrambling for credits.

The wish list works well here, but it takes patience.  There are some members who only post wish list books, and almost only receive books that are from their wish list.  For this to work well, you need a lot of books on your wish list, and patience, especially at first.  Most members have some books coming to them from their wish list, and others that they order from books that are currently available -- from "posted books."

There are 166 books by C. S. Lewis that are currently available. Here's a link to them: http://www.paperbackswap.com/book/browser.php?a=c+s+lewis&s_type=a&oby=ASC&obd=0&ls=0&l=100 Just click the Order This Book button next to any of them to get it.

Also, I agree with Mary that you might want to go ahead and order some books before sending any more out. Just go to My Account / Vacation Hold to prevent any more requests from coming in to your shelf. If you do that, you should also make sure you have your wish list books set to Auto-request. The system will order them for you automatically whenever they're posted, even if your account is otherwise on hold.

Thank you for all the help. I didn't read how this all works in detail. And I haven't been active but the last month, nor put any books up to WL or send. 

Yesterday, I noticed the Digital Art book was no longer available. I guess someone ordered the book. 

Some books take a long time to get.  I've had books especially books used in learning take upwards of a year to get, even if they only had a few wishers when I put the book on my wl.  Some Young Adult, and Erotica books also move pretty slowly.   I've had Spider-Touched (Ghostland World, Bk 2) :: Jory Strong on my wishlist since 6/17/2011.  I've have received many wl books though since then though.  I've got 2 that have been on there since 2010, 8 that have been on since 2011, 26 from 2012 and the rest are from 2013 & 2014.  However though I've received 550 books since becoming a member in 2009 and the majority of those have come from being posted to my wl.  It just takes time so like the others have said the more books you have on your wl the more books that will eventually come your way.  Also the more friends you ad could help you too.  So if there is a genre that your into more you could go that and start getting to know the more active member and friend them.  It helps a lot to have friends who will be willing to look at your wl on the off chance they might have more than one to send to you so that they can save on postage.  Oh and the games forum is also a good way to get wl books too. 

I have a different opinion about keeping credits on hand.  When I first started using the WL function, I had less than 10 credits in my acct. As a newbie, I usually  would order more books as soon as I got credits added to my acct thru swaps.  But one time I got 8 WL offers in one week so that took me down to almost no credits and I don't like being in that position, especially since I often order books for my 3 daughters, one of whom is a HS English teacher.

You might also check the Wishlist Multiples thread in Book Bazaar to see if any of your Wishlisted books are there.  You have to agree to get 2 or more but you might find something you want.

"what is the best way to perceive this situation of sending a lot, and not receiving any. "

There are currently 597,973 unique titles available to request. If you perceive you are not receiving any books, there are plenty there to request.