Once You start with beginner's routine JonPop posted,You will need a good Kegel exercises to add strength to Your penis.
Kegels will make Your penis stronger,Your erections will be firmer,and You will be long-lasting during sex.
Here are some good kegel exercises I found,so You might want to give them a try :
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Kegels for Beginners
The following exercises are simple, effective and very easy to do. These exercises will allow you to build up your PC muscle strength before tackling our intermediate exercises.
Beginner Kegels Exercise I: Urine Flow Pause
Every time you go to the restroom and begin to urinate, stop your urine stream midway and hold it in for as long as you can. Then release, allowing your urine stream to flow freely once again. Repeat several times (at least 5) during each visit to the restroom.
Beginner Kegels Exercise II: Quick Clenches
Quickly clench and unclench your PC muscle for a 10 second period - then take a 10 second break. Repeat 3 times. Note: Each clench may last only a second or less. Just do as many clenches as you can in a 10 second period of time, then stop. Perform three sets of 10 second clenches, then take a 30 second break. Perform (3) 30 second intervals each day. If you are unable to do this many clenches, do as many as you can before your muscle tires out. Each day, strive to do more clenches than the day before. Most beginners are unable to hold a clench for more than 1 or 2 seconds, so this is a great way to effectively build strength for future exercises which require a longer hold.
Beginner Kegels Exercise III: Penis Lifts
In a seated or lying position, attempt to move/lift your penis by flexing your PC muscles. If you are naked, you should see the penis move in some way (most noticeable in semi-erect or fully erect states). However, you do not need to be naked in order to perform this exercise and you do not need to have an erection. Whether you're sitting at home or at work, you can perform this exercise simply by flexing your PC muscles, which will cause your penis to move (or attempt to move). Try to hold the flex for as long as you can each time. Repeat this exercise throughout the day, every single day, as often as you like.
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Intermediate Kegels Exercises
Once you've acquired an adequate amount of strength in your PC muscles, you can step up to our Intermediate PC Exercises. These exercises are guaranteed to take you to the next level of PC strength and sexual improvement.
Intermediate Kegels Exercise I: Basic PC Squeezes
Gradually tighten your PC muscles over a count of five. Then, hold these muscles tight for a count of five and then slowly release them for a count of five to complete the rep (that's a total of 15 seconds per rep). Begin with 10 reps per day and gradually increase to as many as 50 reps per day.
Once you are capable of doing the 50 rep routine, you can scale down your workout. While you want to exercise your PC regularly, you can shift to a maintenance plan. Your maintenance program may consist of 20 reps, 1 - 2 times each day. If at any point sexual enjoyment or your erection strength begins to subside, resume the 50 rep exercise. Remember, you can perform these exercises while watching TV, going to the bathroom or driving to work, so squeeze them in whenever you get a chance.
Kegels Exercise II: Short Squeezes
This exercise is similar to Intermediate Kegels Exercise I; however, you are focusing on shorter, quicker squeezes. Rather than holding the squeeze for a count of 5 each time, hold for a count of 2 (for a total of 6 seconds per rep). Begin with 20 reps per day and gradually increase to as many as 100 reps per day.
Kegels Exercise III: Long, Slow Squeezes
Warm up with a set of 30 short squeezes (1 - 2 seconds each), then tighten as hard and as deeply as you possibly can. When you cannot squeeze any deeper, hold where you are for 20 seconds. Rest for 30 seconds. Repeat 5 times.
After 4 - 6 weeks of daily exercising, you should be able to do this squeeze and hold exercise for at least 1 - 2 minutes at a time, perhaps longer. This particular exercise will give you absolute rock hard erections and the control to last as long as you want in bed. Eventually, work your way up to 10 sets of 2 minute long holds. It may sound like a lot now, but you'll be amazed at how quickly you can build up to that level of strength.
Kegels Exercise IV: The PC Step Workout
This exercise simply involves tightening and relaxing your PC muscle in short steps, or increments. Begin to tighten your PC, hold, then tighten more, hold, a little more, hold, then tighten all that you possibly can and hold. Hold this for 20 seconds, then relax a little bit, hold, relax a little bit more, hold, relax a little more, hold, then finally release the rest. Do this 5 times without resting in between reps.
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Advanced Kegels Exercises
Once you've mastered the intermediate exercises, you may want to give Advanced Kegels Exercises a try.
Advanced Kegels Exercise I: The PC Burn
Begin to tighten your PC muscle very slowly. Tighten so slowly that it takes 3 minutes to completely tighten the muscle. At some point, you will feel that you can no longer tighten your PC, but keep going. Go beyond where you think you can go. Keep tightening until your PC begins to burn. Hold very tightly at that point, and breathe very slowly and deeply for 30 seconds. At the end of 30 seconds, tighten your PC even more, continually trying to push yourself. When the burning becomes uncomfortable, release your hold and immediately do 20 PC squeezes. Perform once daily.
Advanced Kegels Exercise II: The PC Pressure Flex
This exercise must be done in private, as it is not as inconspicuous as our other Kegels exercises.
You will need an erection for this exercise; however, a lubricant is not required unless you need it to jelq yourself to an erection.
Once you have a full erection, grasp your penis midway up the shaft. Use your whole hand, gripping with all fingers. Flex your PC muscle and hold for approximately two seconds. Apply medium, constant pressure to your penis with your gripping hand. You will feel some resistance, since you are containing the blood in the penis. Your penis will also want to rise, but keep it in one place. You are applying pressure against both functions of the PC muscle - blood movement and erection rigidity.
Begin with a set of ten repetitions. This should take approximately 30 seconds to 1 minute, depending on how long you pause between flexes. Do as many sets of ten as you can until you can no longer flex against resistance.
Gradually work your way up to more and more repetitions. If you feel like you're ready for a new challenge, you may want to apply more pressure downwards (not squeezing harder, but pushing down against your PC muscle). The advanced PC exercise should not take more than 3 to 5 minutes total. Perform once daily. You can alternate this daily exercise with the Kegel Burn if you like, or perform both exercises each day.
Good luck,
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Kegels Exercises 
