So, one of your closets - perhaps your master walk-in closet is a long narrow closet. The one we are showing in the image on this post is: 5' Wide x 11 foot Long.
1st Tip - Always PURGE. No doubt you have clothing you bought that has never seen the light of day. Chances are it doesn't fit anymore and it's time to make a local donation. Yes - it still has tags on it too!
2nd Tip - Draw your closet on paper (overhead view). Then find a free design tool online. There are Lots of free tools as well as apps. Once you have the basic outline of your closet, your next step is to physically measure the size of your space with a reliable tape measure. Be sure to add in any windows, light switches, HVAC Vents and any obstruction you see - as well as ceiling height, door and floor trim and more.
Next you want to start to lay out each area of your closet. Remember if it is a walk in to set it up in the most comfortable way. Perhaps shoes should be on the left or right of the door, so you can put them on as you leave the closet.
If your closet is Narrow (like the Image above you will want to place the hanging items on the deeper side and the shelving on the narrow side.
3rd Tip - After you have completed your layout it is always a good idea to take a Painters tape to create an outline on the floor. Remember - no matter how deep the shelving sections are - your clothing on a hangar extends to 22 to 23 " from the wall. Creating this outline on the floor - then walking it off will help you to get a real "Feel" for how comfortable your newly organized closet will be.
4th Bonus Tip - You can always call in a professional - like Custom Home Cabinetry - to create your design for you, They will make as many changes to your design as you feel nare needed - to arrive at the perfect design!