With dress pants, there is that crease that's always there that's sometimes hard to put in there yourself. Often the solution is to just take your pants to the dry cleaners and have them do it. However, there are a couple of ways that you can actually iron that permanent crease yourself and it's not that difficult!
The best way to iron the crease is to use some starch and iron the crease into the pant. You can use the paperclip trick (placing the paperclips along the line of the desired crease to give you direction as you iron) and then apply the starch to the spot as you iron. This is probably the best way to go because it's quick and starch is meant for fabrics anyway. You won't be adding any substance to your fabric that's not meant to be there. When combining the paperclip trick and the starch trick, you'll have no problem creating that permanent crease as you iron
Another way to create that permanent crease is to mix one-third cup of vinegar to two-thirds cup of water. Using a spray bottle, dampen the fabric in the area that you require the permanent crease. Cover with some brown paper or similar and iron. This method is a little less recommended because then your pants will smell like vinegar and you'll want to wash your pants anyway, necessitating another ironing venture. Vinegar fixes a lot of things, but when it comes to ironing it into your clothes, think twice.
Creating the permanent crease you want for your dress pants isn't a secret of the dry cleaners. It's actually achievable in your own home and doesn't take too much extra effort on your part. This way you can wash your dress pants regularly at home and still be able to have that professional look. Hooray for the permanent crease!