Here's a few ways to do that:

1) Make sure that basics are at the rear of the store.  If a customer is shopping for jeans, a black t-shirt, or some other common wardrobe essential, you will want to lure them deeper into the store by moving these items to the back.  Try to ensure that they will pass many other enticing items as they make their way back to the basics.

2) Arrange your other brands with this concept in mind.  If your boutique features a popular name brand of shoes, then customers should have to weave through all the other shoe displays to get to them.  If you have aisles, put the most popular name brands in the center of the aisles.  You don't want customers to easily avoid your other products by grabbing what they need from the end of the aisle.

3) Surround or pair items that you know to be basics with other items that you want to promote.  If you know that people are coming in for that new style of jeans, then you should create interesting displays coordinating those jeans with other items.  Mannequin displays are perfect for this.  Dress the mannequin in a top that goes well with the jeans, and then load it up with accessories, like purses, sunglasses, hats, shoes and jewelry.  

4) Don't make your lighting layout too bright or too dim. The same goes with your music selections. Obtrusive lights or music does not encourage your customer to relax and shop. Do utilize a few tricks to keep your customers in the store. For instance  displaying samples is a good way to make sure that people spend time on your cosmetics aisles. You can even use scented air filters, incense, candles and air fresheners to induce relaxation.

5) Make sure that your shoppers are comfortable and that everything is easy to access.  Don't crowd your displays.  Clothing racks, garment racks, shelves and other displays should not be placed close together.  No one wants to be looking through a clothing rack for their size and be backed up to another customer.  Narrow aisles discourage people from browsing and taking the time to find the items that they're interested in.  Sometimes less is more.

One final suggestion. Have some friends shop your store and ask there opionon of it's “shopability”. Was it easy to find things? Did they get bored quickly? Was the merchandise fun, intesting, compelling, priced right? Was it a great shopping experience? If not, make changes and if you're not sure how, get some expert help.