Muay Thai drills are an integral part of a proper Thai boxing training. And since there is never enough of a good training I would like to share some effective drills with you. You can complete bag drills and agility drills on your own and you will need a sparring partner for a Thai pads drills.
It is recommended to time your bag drill to five 3 minute rounds with a 1-minute break. This way you will condition your body for a regular sparring session or a fight. It is also good to let your muscles "breathe" and replenish itself with the oxygen. Don't stay in one place but rather move around and strike from different angles like in a real fight. Don't forget to change your pace. Mix up fast combinations of punches with slow jabs to control range. Pay attention to your footwork. Start with a basic Jab + Jab and Jab + Cross combo while moving around the bag. You can also mix it up with round kicks. Then grab the bad with both hands a deliver some front knee and side knee strikes.
Once you have warmed up do a little more complicated combinations, like:
[left] Jab + [right] Cross + Left knee + Right elbow (this one is good for a bag drill and no so much for a Thai pad drill - right after that left knee the pad holder would catch an elbow in his face)
[Left] Jab + [Right] Cross + Right switch kick
[Right] Cross + [Left] Hook + Right low kick
Also in general leg kick combinations are practiced with a heavy bag/banana bag, not with Thai pads. The reason is that you don't catch them - you either evade them or block them by raising your leg.
Find more effective combinations for training under this link: Muay Thai combinations
The classic drill consists of x10 (or x100 if you are much more advanced) fast straight kicks for each leg and Jab + Cross boxing combinations. But there is much more to do and you are only limited by your stamina and your body coordination and the experience of the pad holder. You can mix up a various Punch+Kick+Knee+Elbow combinations and evasive moves. When you practise an elbow combos be sure to wear elbow pads. Let's start building muscle memory:
[Left] Jab + [Right] Cross + Left hook + [Right] Cross
[Right] Cross + [Left]Hook + [Right] Cross + [Left] Jab + [Right] Cross + [Left] Uppercut + [Right] Cross
[Right] Cross to body + [Left] Hook + [Right] Uppercut elbow
It may be also used to practice with focus mitts. Focus mitts has got one significant advantage over Thai pads: mitts holder can also strike (he can throw an overhand) - so will have an opportunity to practice head movement and evasion.
Find more effective combinations for training read: Muay Thai combos
Ladder drills are a great exercise to improve your agility and footwork. It improves your movement accuracy and teach you proper footwork patterns. Once you "program" your body to move in certain ways it will work almost effortless during the fight. These exercises condition your body by repetition to act in the desired way so you don't have to think about it during the fight - you just do it automatically.
For more training tips read: Muay Thai Training