Hi. You might want to try out ultrasound-assisted extraction method. After you lightly wash your specimens, you can dry them through freeze-drying method. This method is better than air drying and oven drying because there's no heat involved and there's minimal exposure to air (which can lead to oxidation of compounds). After that, you can process the samples into powder with aid of liquid nitrogen and mortar and pestle. Following this, you may proceed to extraction using the solvent of your choice. This can be done by putting your powdered specimens in glass jars and adding in the solvent. Ultrasound-assisted extraction is applied in this step where you can place the glass jar in a sonicator (also known as ultrasonic bath) for about 10-15 minutes. Then, the solvent containing your extract can be filtered using filter paper. The same powdered specimens in the glass jar should be extracted again using the same method for three times to ensure that most of the compounds are extracted (i.e. adding solvent, sonicate, and collect filtrate). Once you're done extracting the plant, the liquid extract should be concentrated under reduced pressure by using a rotary evaporator. After concentration of the extract, the remaining solvents can be totally removed by using a freeze-drier. Following these procedures, you should obtain your dried plant extract of interest. Hope this help :)

Basically hot extraction gets you good yield and even good metabolite content. But it is with your target which you look for in the specific plant which decides your method of extraction. There are certain constituents which may get lost on hot extraction so you have to go with cold maceration. If the compounds are thermolabile then go with cold maceration. As Mr.Delhousie mentioned can also go with Ultrasound assisted extraction, supercritical fluid extraction, microwave assisted extraction, etc..all these are considered as modern methods of extraction. The conventional methods are Soxhlation(hot continous) and cold maceration.

Extraction is the crucial first step and selection of extractant (solvent) system largely depends on the specific nature of the bioactive compound being targeted. Extraction of hydrophilic (polar) compounds is done using polar solvents such as methanol, ethanol or ethyl-acetate. Various methods, such as sonification, heating under reflux, soxhlet extraction and others are commonly used for the plant samples extraction. In addition, plant extracts are also prepared by maceration or percolation of fresh green plants or dried powdered plant material in water and/or organic solvent systems. The other modern extraction techniques include solid-phase micro-extraction, supercritical-fluid extraction, pressurized-liquid extraction, microwave-assisted extraction, solid-phase extraction, and surfactant-mediated techniques, which possess certain advantages. In your case as you intend to prepare methanol and aqueous extract of Calotropis procera, you can proceed with hot extraction  using soxhlet extraction apparatus followed by distillation of extract under reduced pressure.

Thanks for your helping